KTB1100

KTB1100 KINETIC | Alldatasheet

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Technical content

Features

Wide VIN Range: 7V to 100V
Integrated 1.5A, 150V Power MOSFET Switch
430mΩ (typ.) on-resistance of MOSFET Switch
Integrated Feedback and Digital Isolator
Internal Startup Regulator
±1.5% Feedback Voltage Reference
3kV-rms Isolation
Frequency Adjustable from 100kHz to 1MHz
Adjustable Soft-Start Time
Precision Enable for Adjustable UVLO
Optional Primary Side Bias for Optimized Efficiency
Integrated Cycle-by-Cycle Current Limit, Input UVLO, Over Current Protection, Short-Circuit Protection, and Thermal Shutdown Protection
SOIC-16 Wide Body (10.3mm x 7.5mm)
-40°C to 125°C Operating Junction Temperature Range
Safety Certification: UL1577 (No. E517623) Brief Description The KTB1100 is a highly integrated isolated flyback regulator with integrated power MOSFET switch, internal feedback, and integrated digital isolator. The internal digital isolated eliminates the need to use an external optocoupler and enables small total solution size. The device operates over a wide input voltage range from 7V to 100V to support a variety of applications. The KTB1100 employs current -mode constant on -time (COT) control for fast transient response as well as superior output voltage regulation. The device features an adjustable soft-start function to limit inrush current du ring start-up. The device has integrated protection features including input voltage UVLO, output overvoltage protection (OVP), cycle-by-cycle current limit, short-circuit protection and thermal shutdown. The KTB1100 is available in RoHS and Green compliant SOIC-16 package.

Applications

Battery Management System (BMS) in EVs
Telecom and Communications Power Systems
Industrial PLCs, Smart Meters
Power-Over-Ethernet (PoE)
Bias supply for isolated DC-DC converters
Low power isolated power modules Typical Application VIN SW EN PBIAS FREQ SS SVCC PGOOD VIN PGND SGND PVCC COMP FB SBIAS CSN CSP VOUT KTB1100 I S O L A T I O N Cin 4.7µF x 4 Rsn 100k Dsn ESID Csn 2.7nF Cfeq 680p Cs 100nF Rfeq 121k RCS 22.1K Ccs 22nF Co 47µF x 2 CSVcc 1µF Rcomp 80.6k Rf1 88.7k Rf2 10k Df DST10100S 1µF LM = 35µH NP:NS = 10:7 Ccs Optional Csbias 1µF Ccomp 2.2nF Cfi Optional Ciso 4.7n/2kV 15W Flyback Regulator with Digital Isolator Integrated Feedback

t KTB1100 February 2022 – Revision 04b Page 2 of 20 Company Confidential Pin Descriptions Pin # Name Function 1 SW Drain of Internal Power MOSFET. 2 PGND Primary Side Ground. 3 VIN Input supply voltage with 7V to 100V operating range.

4 PBIAS

Optional input to primary side PVCC bias regulator. Powering PVCC from an external supply instead of VIN can reduce power loss at high VIN. For PBIAS > 8V, the PVCC regulator draws current from PBIAS pin. The PBIAS pin voltage must not exceed 28V. 5 PVCC Output of the primary side PVCC regulator, Connect a capacitor to primary ground PGND.

6 FREQ

Switching frequency programming pin. Refer to the typical application schematic, one external resistor between VIN and FREQ and one capacitor connected between FREQ pin and PGND, are used to set the switching frequency. See Application Section for more details. 7 SS Soft-start programming pin. A capacitor between the SS pin and PGND pin to set soft-start time. 8 EN Enable input, with internal pull-up current source. Pull below 1.2V to disable. Float to enable. The pin can be used to set an adjustable undervoltage lockout with a resistive divider. 9 PGOOD Power good indicator. This pin is an open-drain output. A 10kΩ pullup resistor between PGOOD and SVCC or an external logic supply pin is recommended. 10 COMP Output of the error amplifier. An external RC compensation network connected between COMP and SGND compensates the converter control loop. 11 FB Feedback pin for output voltage regulation. Connect a resistor divider network from the output of converter to the FB pin. 12 SGND Secondary Side Ground. 13 SVCC Output of the secondary side SVCC regulator, Connect a capacitor to secondary ground PGND. 14 SBIAS Input to secondary side SVCC bias regulator.

15 CSN Negative input to current sense amplifier, connect this pin to the VOUT side terminal of the

capacitor of the RC network, refer to the typical application schematic. 16 CSP Positive input to current sense amplifier, connect this pin to the SGND side terminal of the capacitor of RC network, refer to the typical application schematic. Wide Body SOIC-16 Top View PGND VIN EN PGOOD PVCC FB SGND COMP SVCC SS SW PBIAS CSN CSP SBIAS FREQ KTB1100 XXYYZ 16-Lead 10.3mm x 7.5mm x 2.65mm XX = Device Code, YY = Date Code, Z = Serial Number

t KTB1100 February 2022 – Revision 04b Page 3 of 20 Company Confidential Absolute Maximum Ratings1 (TA = 25C unless otherwise noted) Symbol Description Value Units VIN, EN, FREQ High Voltage Pins -0.3 to 100 V PBIAS Medium Voltage Pins -0.3 to 30 V SW High Voltage Pins (100μs duration,10%Duty) -2 to 150 V PVCC, SVCC, PGOOD Low Voltage Pins -0.3 to 6 V SS, FB, COMP Low Voltage Pins -0.3 to 6 V CSN, SBIAS Medium Voltage Pins -0.3 to 54 V CSP Low Voltage Pins -0.3 to 6 V TJ Junction Temperature Range -40 to 150 C Ts Storage Temperature Range -55 to 150 C TLEAD Maximum Soldering Temperature (at leads, 10 sec) 260 C ESD Ratings2 Symbol Description Value Units V(ESD) Electrostatic discharge Human body model (HBM), per ANSI/ESDA/JEDEC JS-001, all pins ±2000 V Charged device model (CDM), per JEDEC specification JESD22-C101, all pins ±500 Thermal Capabilities3 Symbol Description Value Units ΘJA Thermal Resistance – Junction to Ambient 87.0 C/W ΘJC Thermal Resistance – Junction to Case 52.0 C/W PD Maximum Power Dissipation 1.4 W ∆PD/∆T Derating Factor above TA = 25OC -11.5 mW/OC

Ordering Information

Part Number Marking4 Junction Operating Temperature Package KTB1100EYAA-TE XXYYZ -40°C to +125°C SOIC-16 1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions specified is not implied. Only one Absolute Maximum rating should be applied at any one time. 2. ESD Ratings conform to JEDEC industry standards. Some pins may actually have higher performance. Ratings apply with chip enabled, disabled, or unpowered, unless otherwise noted . 3. Junction to Ambient thermal resistance is highly dependent on PCB layout . Values are based on thermal properties of the device when soldered to an EV board. 4. XX = Device Code, YY = Date Code, Z = Serial Number.

t KTB1100 February 2022 – Revision 04b Page 4 of 20 Company Confidential Electrical Characteristics5 Typical values correspond to T A = 25°C. Minimum and Maximum specs are applied over the full operating junction temperature range of -40°C to 125°C, unless otherwise noted. VIN = 24V, unless otherwise noted. Symbol Description Conditions Min Typ. Max Units Supply and Enable VIN Input Voltage Range 7 100 V VIN UVLO VIN Rising 5.2 V VIN Falling 5.0 V IIN Non-Switching Operating Current FB = 2V, PBIAS = 0V 2.5 4 mA ISHDN Shutdown Supply Current EN = 0V 2 5 µA PVCC PVCC Regulator Output Voltage PBIAS = 0V, PVCC open 4.7 V PBIAS = 8 to 28V, PVCC open 4.9 V PVCC Maximum Output Current 15 30 mA PBIAS PBIAS Operating Voltage Range 8 28 V PVCC Regulator Input Switchover Threshold VIN = 24V 7.5 8 V EN EN Pin Voltage to Enable the Device EN rising 1.16 1.24 1.32 V Hysteresis EN falling 140 mV SBIAS SBIAS Operating Voltage Range 3 48 V SVCC SVCC Regulator Output Voltage SBIAS = 3 to 48V, SVCC open 3 V SVCC Maximum Output Current 5 10 mA Power FET RDS(on) POWER MOSFET ON Resistance 430 650 mΩ IDSS Drain to Source Leakage Current EN = 0V, VSW = 120V 10 µA tON FET Minimum ON Pulse Duration 150 ns tOFF FET Minimum OFF Pulse Duration 350 ns tr Rise Time VDS = 48V 20 ns tf Fall Time VDS = 48V 15 ns 5. KTB1100 is guaranteed to meet performance specifications over the –40°C to + 85°C operating ambient temperature range by design, characterization and correlation with statistical process controls .

t KTB1100 February 2022 – Revision 04b Page 5 of 20 Company Confidential Electrical Characteristics5 (continued) Typical values correspond to T A = 25°C. Minimum and Maximum specs are applied over the full operati ng junction temperature range of -40°C to 125°C, unless otherwise noted. VIN = 24V, unless otherwise noted. Symbol Description Conditions Min Typ. Max Units Primary Side OCP ILIM Power MOSFET Current Limit Threshold 1.5 1.9 2.4 A Consecutive Cycles of Cycle-by-Cycle Current Limiting Events before Entering Hiccup Mode 32 Blanking Time in Hiccup Mode 256 ms Secondary Side Current Sense ICSP CSP Pin Input Bias Current 50 nA ICSN CSN Pin Input Bias Current 50 nA GCS Current Sense Gain 10 V/V FB and Error Amplifier VREF Feedback Voltage Reference 1.182 1.2 1.218 V Gm Error Amplifier Transconductance6 240 300 360 μS ROUT Error Amplifier Output Resistance 10 MΩ fBW Unity Gain Bandwidth 2 MHz IFB Error Amplifier Input Bias Current 20 nA ICOMP COMP Sink Current VFB = VREF + 300 mV 200 μA COMP Source Current VFB = VREF - 300 mV 200 μA OV UV and PGOOD PGOOD PGOOD High Threshold (OV) with Respect to VREF VFB Rising 107 110 115 % PGOOD High Hysteresis with Respect to VREF 2 % PGOOD Low Threshold (UV) with Respect to VREF VFB Falling 87 90 93 % PGOOD Low Hysteresis with Respect to VREF 2 Frequency and SS fSW Switching Frequency Range6 100 1000 kHz ISS Soft-start Pull-up Current 5 μA Thermal Shutdown TJ_SHDN Thermal Shutdown Set Threshold TJ rising 150 °C TJ_hys Thermal Shutdown Hysteresis 30 °C Insulation Specifications VISO Isolation Voltage 1 minute duration, ac RMS 3 kV 6. Guaranteed by design, characterization and statistical process c ontrol methods; not production tested.

t KTB1100 February 2022 – Revision 04b Page 6 of 20 Company Confidential Typical Characteristics VIN = 9V-75V, VOUT = 12V, RFREQ = 121kΩ, CFREQ = 680pF, Transformer (Np:Ns = 10:7, Lp = 35µH), TJ = 25°C unless otherwise specified. VREF Temperature Regulation EN Rising Threshold vs Temperature EN Falling Threshold vs Temperature MOSFET Current Limit vs Temperature MOSFET Current Limit vs Input Voltage Soft-start Pull-up Current vs Temperature 1.180 1.185 1.190 1.195 1.200 1.205 1.210 1.215 1.220 -40 -20 0 20 40 60 80 100 120 140 VREF (V) Junction Temperature (ºC) 1.2 1.21 1.22 1.23 1.24 1.25 1.26 1.27 1.28 -40 -20 0 20 40 60 80 100 120 140 EN rising Threshold (V) Junction Temperature (°C) 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 -40 -20 0 20 40 60 80 100 120 140 EN Rising Threshold (V) Junction Temperature (°C) 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 -40 -20 0 20 40 60 80 100 120 140 MOSFET Current Limit (A) Junction Temperature (°C) 0.9 1.4 1.9 2.4 12 18 24 30 36 42 48 54 60 66 72 78 MOSFET Current Limit (A) Input Voltage (V) 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 -40 -20 0 20 40 60 80 100 120 140 Soft-start Pull-up Current (μA) Junction Temperature (°C)

t KTB1100 February 2022 – Revision 04b Page 7 of 20 Company Confidential Typical Characteristics – 12V Output VIN = 9V-75V, VOUT = 12V, RFREQ = 121kΩ, CFREQ = 680pF, Transformer (Np:Ns = 10:7, Lp = 35µH), TJ = 25°C unless otherwise specified. Switching Frequency vs Input Voltage Maximum Output Current vs Input Voltage Efficiency VREF Load Regulation VREF Line Regulation Switching Frequency vs Capacitance 300 350 400 450 500 550 600 650 700 750 800 12 18 24 30 36 42 48 54 60 66 72 78 Switching Frequency (KHz) Input Voltage (V) Rfeq = 89K, Cfeq = 680pF, Io = 0.5A Rfeq = 89K, Cfeq = 680pF, Io = 1A 0.9 1.4 1.9 2.4 6 12 18 24 30 36 42 48 54 60 66 72 78 Output Current (A) Input Voltage (V) Efficiency (%) Load Current (A) 24Vin 36Vin 48Vin 60Vin 1.188 1.192 1.196 1.200 1.204 1.208 1.212 VREF Voltage (V) Load Current (A) 24Vin 36Vin 48Vin 60Vin 1.188 1.193 1.198 1.203 1.208 1.213 0 12 24 36 48 60 72 84 VREF Voltage (V) Input Voltage（V) 100 200 300 400 500 600 700 800 900 1000 330 630 930 1230 1530 1830 2130 Switching Frequency (kHz) CFREQ (pF) Rfeq = 89K, Vin = 24V, Iload = 1A RFREQ = 89kΩ, CFREQ = 680pF, IO = 0.5A RFREQ = 89kΩ, CFREQ = 680pF, IO = 1A RFREQ = 89kΩ, VIN = 24V, ILOAD = 1A

t KTB1100 February 2022 – Revision 04b Page 8 of 20 Company Confidential Typical Characteristics – 12V Output VIN = 9V-75V, VOUT = 12V, RFREQ = 121kΩ, CFREQ = 680pF, Transformer (Np:Ns = 10:7, Lp = 35µH), TJ = 25°C unless otherwise specified. Output Ripple Stable Working at CCM (48VIN, 12VO, IO = 2A, CO = 150µF) (48VIN, 12VO, IO = 1.5A) Stable Working at CCM Stable Working at DCM (24VIN, 12VO, IO = 1A) (24VIN, 12VO, IO = 0.2A ) Stable Working at Burst Mode Enable Startup (24VIN, 12VO, IO = 0A) (24VIN, 12VO, IO = 1A) 1µs / div Vo/AC 50mV / div Io 1A / div 2µs / div Vo 5V / div VIN 50V / div VSW 50V / div Io 1A / div 2µs / div VSW 50V / div VIN 50V / div Vo 5V / div ISW 0.5A / div 2µs / div VSW 20V / div Vo/AC 100mV / div ISW 1A / div 1ms / div VSW 20V / div Vo/AC 100mV / div Io 1A / div 40ms / div VENABLE 2V / div Vo 2V / div

t KTB1100 February 2022 – Revision 04b Page 9 of 20 Company Confidential Typical Characteristics – 12V Output VIN = 9V-75V, VOUT = 12V, RFREQ = 121kΩ, CFREQ = 680pF, Transformer (Np:Ns = 10:7, Lp = 35µH), TJ = 25°C unless otherwise specified. Enable Turn Off Input Startup (24VIN, 12VO, IO = 1A) (48VIN, 12VO, IO = 1.5A) Input Shutdown Dynamic Load Performance (48VIN, 12VO, IO = 1.5A) (24VIN, 12VO, Load Step from 0.5A-1A-0.5A) Short Circuit Performance (12VO, IO from 1A to Short) Vo 2V / div 4ms / div PGOOD 1V / div VEN 10V / div ISW 1A / div Io 1A / div 10ms / div Vo 5V / div VIN 50V / div Io 1A / div 10ms / div Vo 5V / div VIN 50V / div Io 500mA / div 200µs / div Vo/AC 200mV / div ISW 2A / div 4µs / div VSW 20V / div Vo 10V / div

t KTB1100 February 2022 – Revision 04b Page 10 of 20 Company Confidential Typical Characteristics – 5V Output VIN = 9V-75V, VOUT = 5V, RFREQ = 150kΩ, CFREQ = 1.5nF, Transformer (Np:Ns = 6:1, Lp = 120µH), TJ = 25°C unless otherwise specified. Switching Frequency vs Input Voltage Maximum Output Current vs Input Voltage Efficiency VREF Load Regulation VREF Line Regulation Switching Frequency vs Capacitance 100 150 200 250 300 350 400 12 18 24 30 36 42 48 54 60 66 72 78 Switching Frequency (KHz) Input Voltage (V) Rfeq=150K,Cfeq=1.5nF,Io=1.5A Rfeq=150K,Cfeq=1.5nF,Io=3A 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 6 12 18 24 30 36 42 48 54 60 66 72 78 Output Current (A) Input Voltage (V) 70% 72% 74% 76% 78% 80% 82% 84% 86% 88% Efficiency (%) Load Current (A) 24Vin 36Vin 48Vin 60Vin 1.188 1.192 1.196 1.200 1.204 1.208 1.212 VREF Voltage (V) Load Current (A) 24Vin 36Vin 48Vin 60Vin 1.188 1.193 1.198 1.203 1.208 0 12 24 36 48 60 72 VREF Voltage (V) Input Voltage (V） 100 200 300 400 500 600 700 800 900 1000 330 630 930 1230 1530 1830 2130 Switching Frequency (KHz) CFREQ (pF) Rfeq=150K,Vin=24V,Iload=…RFREQ = 150kΩ, VIN = 24V, ILOAD = 3A RFREQ = 150kΩ, CFREQ = 1.5nF, IO = 1.5A RFREQ = 150kΩ, CFREQ = 1.5nF, IO = 3A

t KTB1100 February 2022 – Revision 04b Page 11 of 20 Company Confidential Typical Characteristics – 5V Output VIN = 9V-75V, VOUT = 5V, RFREQ = 150kΩ, CFREQ = 1.5nF, Transformer (Np:Ns = 6:1, Lp = 120µH), TJ = 25°C unless otherwise specified. Output Ripple Stable Working at CCM (48VIN, 5VO, IO = 3A, CO = 47µF) (48VIN, 5VO, IO = 3A) Stable Working at CCM Stable Working at DCM (24VIN, 5VO, IO = 3A) (24VIN, 5V0, I0 = 1A) Stable Working at Burst Mode Enable Startup (48VIN, 5VO, IO = 0A) (24VIN, 5VO, IO = 3A) 2µs / div Vo / AC 50mV / div Io 1A / div 2µs VSW 50V / div Vo 5V / div Vin 50V / div Io 1A / div 2µs / div Vo 5V / div VSW 50V / div Vin 50V / div VSW 50V / div 2µs / div Vo 5V / div Isw 0.5A / div Vin 50V / div Isw 1A / div 2ms / div Vo / AC 200mV / div Vin 50V / div VSW 50V / div Io 5A / div 10ms / div VEN 10V / div Vin 50V / div Vo 5V / div

t KTB1100 February 2022 – Revision 04b Page 12 of 20 Company Confidential Typical Characteristics – 5V Output VIN = 9V-75V, VOUT = 5V, RFREQ = 150kΩ, CFREQ = 1.5nF, Transformer (Np:Ns = 6:1, Lp = 120µH), TJ = 25OC unless otherwise specified. Enable Turn Off Input Startup (24VIN, 5VO, IO = 3A) (48VIN, 5VO, IO = 3A) Input Shutdown Dynamic Load Performance (48VIN, 5VO, IO = 3A) (48VIN, 5VO, Load Step from 1A-3A-1A) Short Circuit Performance (48VO, 5Vo, IO from 3A to Short) Io 5V / div 10ms / div Vo 5V / div Vin 50V / div VEN 10V / div Io 5V / div 10ms / div Vo 5V / div Vin 50V / div Io 5A / div 10ms / div Vo / AC 5V / div Vin 50V / div Vo / AC 500mA / div 400µs / div Vin 50V / div Io 5A / div ISW 5A / div 10µs / div Vo 5V / div Vin 50V / div VSW 50V / div

t KTB1100 February 2022 – Revision 04b Page 13 of 20 Company Confidential Block Diagram LDO ILIM Short Circuit Protection LDO 1.2V 1.284V Error Amp CSP CSN FB COMP SGND SBIAS SVCC PGOOD SW PGND VIN EN FREQ PVCC PBIAS SS Current Sense Amp OVP Comparator 0.6V R SQ QN 1.2V 3.9V LEB S R Q QN 2.5V Control Logic Control Logic Isolation Barrier Thermal Shutdown UVLOUVLO LDO FB 1.32V 1.08V PVCC 25kΩ Functional Description Overview The KTB1100 is a highly integrated isolated flyback regulator with digital isolator, integrated primary power MOSFET and secondary feedback circuit. It employs current-mode constant on-time (COT) control. KTB1100 offers a complete solution for an isolated flyback dc-to-dc power supply by integrating the 3kV digital isolator, the primary MOSFET and secondary feedback circuitry in one package. The device operates over a wide input voltage range from 7V to 100V supporting a variety of applications. The output voltage can be set by an external resistive divider, allowing KTB1100 to be used in many applications. Digital isolator is integrated in the KTB1100 to eliminate the optocoupler that transmit the output voltage condition from secondary to primary . Integrating the digital isolator reduces system design complexity, cost, and component count and improves overall system performance and reliability. Traditionally in a flyback converter, a discrete optocoupler is used in the feedback path to transmit the signal from the secondary to the primary side. However, the current transfer ratio (CTR) of optocouplers can degrade over time and over temperature. If it is not considered during the design, it can reduce the long-time system reliability . Secondly, most discrete optocouplers used in telecom or industrial applications have a maximum operation temperature of approximately 100°C to 125°C, potentially limiting the maximum operating temperature of the system. The KTB1100 eliminates the use of a discrete optocoupler, thereby reducing system cost, PCB area, and complexity, while improving system reliability and increasing the maximum operating temperature of the system. The primary-side 150V power MOSFET is integrated in the KTB1100 to reduce system cost and size . This primary 150V power MOSFET has a 0.43Ω RDS_ON and can work up to a peak current of 1.9A before current limit is triggered . The KTB1100 primary-side MOSFET incudes a current limit function and w hen the current

t KTB1100 February 2022 – Revision 04b Page 14 of 20 Company Confidential exceeds its peak current limit for 32 cycles, the KTB1100 will shut down and enters hiccup mode with a 256ms time interval. Secondary feedback circuitry is integrated in the KTB1100 to eliminate external voltage reference and error amplifier. The integrated voltage reference has a better than ±1% accuracy, while the error amplifier has a high gain bandwidth. The primary circuitry in the KTB1100 includes a 4.8V LDO, a primary power MOSFET with current sensing, optional bias circuit, and PWM generator. The secondary circuitry includes the error amplifier, an internal voltage reference, a 3V LDO regulator, and a dedicated pin for power good indication. PWM signal is controlled both by the constant on-time control of the primary side and the valley current mode control in the secondary side of KTB1100. Current sensing is performed on the secondary side by sensing the output current of the secondary transformer winding cycle by cycle. The output voltage of the converter is sensed by the error amplifier on the secondary side, sending a signal to the primary side via the 3kV integrated digital isolator for a complete control loop solution. KTB1100 offer features such as input undervoltage lockout (UVLO), precision enable with hysteresis, output overload current limit (OCL) short circuit protection (SCP), output overvoltage protection (OVP), over temperature protection (OTP), and power saving with burst mode in light load conditions. Enable KTB1100 flyback regulator is turned on and off using the EN pin. If the EN pin is high or floating the regulator is enabled. Pulling the EN pin low will disable the regulator. EN pin maximum rating voltage allows connection to Vin pin for simple control. Enable high logic threshold is 1.24V with a 0.1V hysteresis voltage. Connecting a resistive divider between EN and VIN sets the input start-up voltage with hysteresis. To prevent noise, it is recommended to connect a capacitor on the EN pin to PGND. Please r efer to the application circuit in Figure 1. Soft-Start To provide a controlled startup, a capacitor is required on the SS pin. At device power on, the SS capacitor is slowly charged by an internal 5µA current source, increasing the switching frequency thereby limiting the input in-rush current. This will slowly increase until the operating switching frequency set by RFEQ and CFEQ is reached. Internal Switching FET The SW and PGND provide connection to the drain and source of the integrated switching power MOSFET. This 150V MOSFET has a typ ical 0. 43Ω RDS_ON. It is used as a p rimary power switch for the flyback DCDC converter. The internal MOSFET gate driver is powered from PVCC voltage rail, and the return path is through the GND pin. As the large leakage inductance of the flyback transformer and high peak current of primary power MOSFET, there will be a high voltage stress produced on the SW node of KTB1100, especially at high input voltage. Therefore, a RCD snubber circuit for SW node is recommended. It is recommended that RCD values are selected to keep the voltage at SW at less than 120V during normal operation. Primary Optional Bias Supply There is an optional input to primary side PVCC bias regulator that can be powered from an external supply instead of VIN . This can reduce the power loss at high input voltages. For PBIAS > 8V, the PVCC regulator draws current from PBIAS pin. The PBIAS pin voltage must not exceed 28V. For most applications, it is recommended to use PBIAS function for higher system efficiency when input voltage is over 48V. An auxiliary primary winding of the transformer is generally used for this function. Primary Side PVCC Regulator A high voltage LDO regulator is connected to the VIN or PBIAS and provides a regulated output at PVCC. PVCC is the output of the primary side PVCC regulator, to power the internal FET gate driver and other internal control circuitry. Connect a 1µF capacitor from PVCC to primary ground PGND . PVCC is 4.7V when regulated from VIN. If a voltage over 8V is supplied through PBIAS, the PVCC pin voltage is 4.9V.

t KTB1100 February 2022 – Revision 04b Page 15 of 20 Company Confidential Secondary Bias Supply SBIAS is the input to secondary side SVCC bias regulator. SBIAS is a high voltage input that can be directly connected to the output voltage. Alternatively, it can be also connected to an auxiliary secondary winding of transformer to improve system efficiency. Secondary Side SVCC Regulator SVCC is the output of the second ary side SVCC regulator and is typically 3V . Connect a 1 µF capacitor to secondary ground PGND. Frequency Switching frequency can be programmed by an external resistor, Rfeq, connected between VIN and FREQ and an external capacitor, Cfeq, connected from FREQ to PGND, as shown in figure 1. The switching frequency during CCM (continuous current mode ), is constant and reduces during DCM (discontinuous current mode). During light load, the regulator will enter burst mode, only switching to replenish the output capacitor to save power and therefore increase the system efficiency. Compensation An external RC compensation network connected between COMP (output of the error amplifier ) and SGND compensates the converter control loop to provide system stability. Current Sense An external RC network is required for the current sense signal function. The current sense signal should be differentially sensed by CSP and CSN. For further details please refer to the application circuit in figure 1 and the layout guidelines. Power Good KTB1100 has a power good indicator. This pin is an open-drain output. A 10kΩ to 100kΩ pullup resistor between PGOOD and SVCC or an external logic supply. Thermal Protection The KTB1100 provides thermal protection by the continuous monitoring of the die junction temperature. Thermal protection is triggered when the di e junction temperature reaches 150°C. When the die junction temperature falls below 120°C, the KTB1100 will be turned on again.

t KTB1100 February 2022 – Revision 04b Page 16 of 20 Company Confidential

Application Information

Typical Application Circuit Figure1 is the application circuit of KTB1100. The KTB1100 is a highly integrated isolated flyback regulator with digital isolator, primary power MOSFET and secondary feedback circuit. It can offer a complete solution for an isolated flyback dc-to-dc power supply. The flyback power supply is typically used to convert a wide input range DC voltage to an isolated DC output voltage. The device can operate over a wide input voltage range from 7V to 100V to support a variety of applications. The output voltage can be programmed to a variety of voltages such as 5V, 12V, 24V and 48V. This section presents a simplified discussion of the design process. VIN SW EN PBIAS FREQ SS SVCC PGOOD VIN PGND SGND PVCC COMP FB SBIAS CSN CSP VOUT KTB1100 I S O L A T I O N Cin 4.7µF x 4 Rsn 100k Dsn ESID Csn 2.7nF Cfeq 680p Cs 100nF Rfeq 121k RCS 22.1K Ccs 22nF Co 47µF x 2 CSVcc 1µF Rcomp 80.6k Rf1 88.7k Rf2 10k Df DST10100S 1µF LM = 35µH NP:NS = 10:7 Ccs Optional Csbias 1µF Ccomp 2.2nF Cfi Optional Ciso 4.7n/2kV Figure 1. Application Circuit parameters of the transformer are turns ratio, inductance, saturation current and so on. current, power MOSFET and diode voltage stress and so on.

t KTB1100 February 2022 – Revision 04b Page 17 of 20 Company Confidential The transformer turns ratio is calculated as follows: 𝑛 = 𝑉𝑖𝑛_𝑚𝑖𝑛∗𝐷𝑚𝑎𝑥 (𝑉𝑜𝑚𝑎𝑥+𝑉𝑑)∗(1−𝐷𝑚𝑎𝑥) Equation (1) Where, n = the turns ratio from primary winding to secondary winding Vin_min = the min. operating input voltage Vo_max = the max. output voltage Vd = the forward voltage drop of secondary rectifier diode. Dmax = max. duty cycle, (the max. duty cycle of the flyback converter is approx. 70%) The flyback transformer primary inductance is calculated as follows: 𝐿𝑚 = 𝑛∗𝑉𝑖𝑛∗𝐷∗(1−𝐷) 𝐹𝑠𝑤∗𝐼𝑜∗𝐾𝑐 Equation (2) Where, Lm = the primary inductance of flyback transformer n = the turns ratio from primary winding to secondary winding Vin = the operating input voltage D = duty cycle. Fsw = Switching frequency Io = Output current Kc = is the ripple current coefficient compared with output current. The value of Kc is normally selected between 0.5 to 1.5 The primary side peak current is calculated as follows: 𝐼𝑝𝑒𝑎𝑘 = 𝐼𝑜 𝑛∗(1−𝐷) + 𝑉𝑖𝑛∗𝐷 2𝐹𝑠𝑤∗𝐿𝑚 Equation (3) Where, Io = Output current n = the turn ratio from primary winding to secondary winding D = duty cycle Vin = the operating input voltage D = duty cycle Fsw = Switching frequency Lm = the primary inductance of flyback transformer

t KTB1100 February 2022 – Revision 04b Page 18 of 20 Company Confidential Frequency Setting The KTB1100 employs current -mode, constant on-time (COT) control for fast transient response as well as superior output voltage regulation. The switching frequency of KTB1100 can be set by the value of Rfeq and Cfeq as shown in figure 1. To set the frequency, first choose the value of Rfeq, and then set the Cfeq to achieve the target switching frequency, as shown in the following: 𝑅𝑓𝑒𝑞 = 𝑛∗𝑉𝑜∗𝑅𝑖 𝑉𝑑𝑑 Equation (4) 𝐹𝑠𝑤 = 𝑛∗𝑉𝑜 𝑉𝑡∗𝑅𝑓𝑒𝑞∗𝐶𝑟𝑒𝑞 Equation (5) Where, n = the turn ratio from primary winding to secondary winding Vo = the target output voltage Ri = the internal resistance of KTB1100, internally fixed at 25kΩ Vdd = the internal power supply of KTB1100, internally fixed at 4.8V Vt = the internal comparator threshold of KTB1100, internally fixed at 0.6V Rfeq = the frequency set resistor Cfrq = the frequency set capacitor Current Sense RC Net Setting The KTB1100 uses the secondary current sense signal for control . The correct Rcs and Ccs values are calculated as follows: 𝑅𝑐𝑠∗𝐶𝑐𝑠 = 𝐾 ∗ 𝐿𝑜 𝐷𝐶𝑅 Equations (6) Where, Lo = the inductance of the secondary side transformer winding, DCR = the resistance of the secondary side transformer winding. Rcs = the resistor of current sense RC network. Its value should be as large as possible to minimize the power dissipation. A recommend value is between10kΩ and 100kΩ. Ccs = the capacitor of current sense RC network. K = the coefficient, with a typical value of 1, and the suggested range is between 0.5 and 1.5.

t KTB1100 February 2022 – Revision 04b Page 19 of 20 Company Confidential PCB Layout Guidelines The following guidelines are recommended for optimum performance. 1. Keep the power stage loop area as small as possible. This includes the input loop (Cin, Transformer, Internal FET of KTB1100) and the output loop (Transformer, Co, Rectifier Diode). 2. Use a single point connection between signal GND (SGND of KTB1100) and output power GND (The negative terminal of the output voltage). 3. Ground all the control capacitors to their respective grounds and place the control circuit capacitors close to the IC to decouple noise. 4. Keep the primary and secondary control circuit trace far away from noise sources (such as primary switch node and secondary switch node). 5. CSP and CSN pins should differentially sense the current signal through the sense components. A 100Ω to 1kΩ filter resistor is suggested in series with each CSP and CSN pins. The CSP and CSN traces should not cross any switch nodes. 6. Keep FB and COMP pins far from high noise sources. In some high output current applications, a typically 10kΩ resistor is suggested to insert between FB pin and output resistor divider network to filter noise. 7. As snubber circuit like RCD should be used to limit peak voltage on the SW pin at turn-off. Minimize the loop from the RCD snubber components to the transformer and IC.

t KTB1100 February 2022 – Revision 04b Page 20 of 20 Company Confidential Packaging Information SOIC-16 (10.30mm x 7.50mm x 2.65mm) E LL1 C Өh D AA2A1 Top View Side View End View be Recommended Footprint 0.60mm (NSMD) Pad Type 9.49mm 2.06mm 7.22mm Dimension mm Min. Typ. Max. A 2.15 – 2.65 A1 0.10 – 0.30 A2 2.05 – 2.55 b 0.31 – 0.51 C 0.10 – 0.33 D 10.10 10.30 10.50 E 9.97 10.30 10.63 E1 7.40 7.50 7.60 e 1.27 BSC h 0.25 – 0.75 L 0.40 – 1.27 L1 1.4 BSC Ө° 0 – 8 Kinetic Technologies cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Kinetic Technologies product. No intellectual property or circuit patent licenses are implied. Kinetic Technologies reserves the right to change t he circuitry and specifications without notice at any time .

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15W Flyback Regulator with Digital Isolator Integrated Feedback February 2022 - Revision 04b

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