MIC5022 MICREL | Alldatasheet

Document overview

  • Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
  • PDF pages: 9

Technical content

Features

  • 12V to 36V operation
  • 600ns rise time into 1000pF (high side)
  • TTL compatible input with internal pull-down resistor
  • Outputs interlocked to prevent cross conduction
  • TTL compatible enable
  • Fault output indication
  • Individual overcurrent limits
  • Gate protection
  • Internal charge pump (high-side)
  • Current source drive scheme reduces EMI

Applications

  • Motor control
  • Switch-mode power supplies General Description The MIC5022 half-bridge MOSFET driver is designed to operate at frequencies up to 100kHz (5kHz PWM for 2% to 100% duty cycle) and is an ideal choice for high speed applications such as motor control and SMPS (switch mode power supplies). A rising or falling edge on the input results in a current source pulse or sink pulse on the gate outputs. This output current pulse can turn on a 2000pF MOSFET in approximately 1ms. The MIC5022 then supplies a limited current (< 2mA), if necessary, to maintain the output states. Two overcurrent comparators with nominal trip voltages of 50mV make the MIC5022 ideal for use with current sensing MOSFETs. External low value resistors may be used instead of sensing MOSFETs for more precise overcurrent control. Optional external capacitors placed on the C TH and CTL pins may be used to individually control the current shutdown duty cycles from approximately 20% to <1%. Duty cycles from 20% to about 75% are possible with individual pull-up resis- tors from C TL and CTH to VDD . An open collector output provides a fault indication when either sense input is tripped. The MIC5022 is available in 16-pin wide SOIC and 14-pin plastic DIP packages. Other members of the MIC502x family include the MIC5020 low-side driver and the MIC5021 high-side driver. Typical Application VDD Input Fault C TH Enable C TL Gnd VBOOST Gate H Sense H– Sense H+ Gate L Sense L– Sense L+ C TL C TH 10µF R S1 R S2 2.7nF M +12V to +36V MIC5022 TTL Input (PWM signal) DC Motor Control Application

Ordering Information

Part Number Temperature Range Package MIC5022BWM –40 °C to +85°C 16-pin Wide SOIC MIC5022BN –40 °C to +85°C 14-pin Plastic DIP

September 1999 179 MIC5022 MIC5022 Micrel Pin Description DIP Pin No. SOIC Pin No. Pin Name Pin Function 11 V DD Supply: +12V to +36V. Decouple with ‡ 10mF capacitor. 2 3 Input TTL Compatible Input: Logic high turns the high-side external MOSFET on and the low-side external MOSFET off. Logic low turns the high-side external MOSFET off and the low-side external MOSFET on. An internal pull-down returns an open pin to logic low. 3 4 Fault When either sense voltage exceeds threshold, open collector output is open circuit for 5ms (tG(ON) ), then pulled low for tG(OFF). tG(OFF) is adjustable from C T.

45 C TH Retry Trimming Capacitor, High Side: Controls the off time (tG(OFF)) of the

overcurrent retry cycle. (Duty cycle adjustment.)

  • Open = approx. 20% duty cycle.
  • Capacitor to Ground = approx. 20% to < 1% duty cycle.
  • Pullup resistor = approx. 20% to approx. 75% duty cycle.
  • Ground = maintained shutdown upon overcurrent condition. 5 6 Enable Output Enable: Disables operation of the output drivers; active high. An internal pull-down returns an open pin to logic low. 67 C TL Retry Trimming Capacitor, Low Side: Same function as CTH . 7 8 Gnd Circuit Ground 8 8 Sense L + Current Sense Comparator (+) Input, Low Side: Connect to source of low- side MOSFET. A built-in offset (nominal 50mV) in conjunction with R SENSE sets the load overcurrent trip point. 9 10 Sense L – Current Sense Comparator (–) Input, Low Side: Connect to the negative side of the low-side sense resistor. 10 11 Gate L Gate Drive, Low Side: Drives the gate of an external power MOSFET. Also limits VGS to 15V max. to prevent Gate to Source damage. Will sink and source current. 11 12 Sense H + Current Sense Comparator (+) Input, High Side: Connect to source of high- side MOSFET. A built-in offset (nominal 50mV) in conjunction with RSENSE sets the load overcurrent trip point. 12 13 Source H – Current Sense Comparator (–) Input, High Side: Connect to the negative side of the high-side sense resistor. 13 14 Gate H Gate Drive, High Side: Drives the gate of an external power MOSFET. Also limits VGS to 15V max. to prevent Gate to Source damage. Will sink and source current. 14 15 V BOOST Charge Pump Boost Capacitor: A bootstrap capacitor from VBOOST to the MOSFET source pin supplies charge to quickly enhance the external MOSFET’s gate . Pin Configuration (N) (WM) 11 4 VDD VBOOST Input Fault CTH Enable CTL Gnd Gate H Sense H– Sense H+ Gate L Sense L– Sense L+ VDD VBOOST Input Fault CTH Enable C TL Gnd Gate H Sense H– Sense H+ Gate L Sense L– Sense L+ NC NC

MIC5022 180 September 1999 Block Diagram C INT 2I1 ONE- SHOT VDD Gate L Fault C TL OFF ON Fault Normal I210I2 15V Sense H– Sense H+ 6V Internal Regulator C INT 2I1 50mV Input ONE- SHOT Gate H C TH OFF ON Fault Normal I210I2 15V CHARGE PUMP VDD VBOOST Enable Sense L– Sense L+ 50mV 1.4V 1.4V fl fl Transistor Count: 188 Absolute Maximum Ratings Timer Voltage (C Operating Ratings Temperature Range

September 1999 181 MIC5022 MIC5022 Micrel

Electrical Characteristics

TA = 25°C, Gnd = 0V, VDD = 12V, Gate CL = 1500pF (IRF540 MOSFET) unless otherwise specificed Symbol Parameter Condition Min Typ Max Units D.C. Supply Current V DD = 12V, Input = 0V 2.5 5 mA VDD = 36V, Input = 0V 6.0 10 mA VDD = 12V, Input = 5V 2.4 5 mA VDD = 36V, Input = 5V 3.0 25 mA Input Threshold 0.8 1.4 2.0 V Input Hysteresis 0.1 V Input Pull-Down Current Input = 5V 10 20 40 mA Enable Threshold 0.8 1.4 2.0 V Enable Hysteresis 0.1 V Fault Output Fault Current = 1.6mA 0.15 0.4 V Saturation Voltage Note 1 Fault Output Leakage Fault = 36V –1 0.01 +1 mA Current Limit Thresh., Low-SideNote 2 30 50 70 mV Current Limit Thresh., High-SideNote 2 30 50 70 mV Gate On Voltage, High-Side V DD = 12V, Note 3 16 18 21 V VDD = 36V, Note 3 46 49 52 V Gate On Voltage, Low-Side V DD = 12V, Note 3 10 11 V VDD = 36V, Note 3 14 15 18 V tG(ON) Gate On Time, Fixed Sense Differential > 70mV 2 5 10 ms tG(OFF) Gate Off Time, Adjustable Sense Differential > 70mV, CT = 0pF 10 20 50 ms tDLH Gate Turn-On Delay, High-SideNote 4 1.4 2.0 ms tR Gate Rise Time, High-Side Note 5 0.8 1.5 ms tDHL Gate Turn-Off Delay, High-SideNote 6 1.2 2.0 ms tF Gate Fall Time, High-Side Note 7 0.6 1.5 ms tDLH Gate Turn-On Delay, Low-Side Note 4 1.7 2.5 ms tR Gate Rise Time, Low-Side Note 8 0.7 1.5 ms tDHL Gate Turn-Off Delay, Low-SideNote 9 0.5 1.0 ms tF Gate Fall Time, Low-Side Note 10 1.0 1.5 ms Note 1 Voltage remains low for time affected by CT. Note 2 When using sense MOSFETs, it is recommended that RSENSE < 50W . Higher values may affect the sense MOSFET’s current transfer ratio. Note 3 DC measurement. Note 4 Input switched from 0.8V (TTL low) to 2.0V (TTL high), time for Gate transition from 0V to 2V. Note 5 Input switched from 0.8V (TTL low) to 2.0V (TTL high), time for Gate transition from 2V to 17V. Note 6 Input switched from 2.0V (TTL high) to 0.8V (TTL low), time for Gate transition from 20V (Gate on voltage) to 17V. Note 7 Input switched from 2.0V (TTL high) to 0.8V (TTL low), time for Gate transition from 17V to 2V. Note 8 Input switched from 0.8V (TTL low) to 2.0V (TTL high), time for Gate transition from 2V to 10V. Note 9 Input switched from 2.0V (TTL high) to 0.8V (TTL low), time for Gate transition from 15V (Gate on voltage) to 10V. Note 10 Input switched from 2.0V (TTL high) to 0.8V (TTL low), time for Gate transition from 10V to 2V.

MIC5022 182 September 1999 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 5 1 01 52 02 53 03 54 0 ISUPPLY (mA) VSUPPLY (V) Supply Current vs. Supply Voltage VIN = 0V VIN = 5V 5 1 01 52 02 53 03 54 0 VGATE H (V) VSUPPLY (V) Gate to Source Voltage vs. Supply Voltage 0.0 0.5 1.0 1.5 2.0 2.5 5 1 01 52 02 53 03 54 0 tON 4V (mS) VSUPPLY (V) Gate Turn-On Delay vs. Supply Voltage VGATE = VSUPPLY + 4V C L = CH = 1500pF C BOOST = 0.01mF NOTE: INCLUDES PROPAGATION DELAY & CROSS CONDUCTION LOCKOUT 0.5 1.5 2.5 5 1 01 52 02 53 03 54 0 tON 10V (mS) VSUPPLY (V) Gate Turn-On Delay vs. Supply Voltage VGATE H = VSUPPLY + 10V C L = CH = 1500pF C BOOST = 0.01mF NOTE: INCLUDES PROPAGATION DELAY & CROSS CONDUCTION LOCKOUT 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 1x10 0 1x101 1x102 1x103 1x104 1x105 tON (mS) C GATE (pF) Gate Turn-On/Off Delay vs. Gate Capacitance HIGH-SIDE VGATE H = VSUPPLY + 4V C L = CH VSUPPLY = 12V NOTE: INCLUDES PROPAGATION DELAY & CROSS CONDUCTION LOCKOUT PROP. DELAY 1.0 1.5 2.0 2.5 3.0 3.5 1x10 0 1x101 1x102 1x103 1x104 1x105 tON (mS) C GATE (pF) Gate Turn-On/Off Delay vs. Gate Capacitance LOW-SIDE VGATE L = 4V C L = CH VSUPPLY = 12V NOTE: INCLUDES PROPAGATION DELAY & CROSS CONDUCTION LOCKOUT PROP. DELAY Typical Characteristics 0.1 1 10 100 1000 10000 RETRY DUTY CYCLE (%) C TH (pF) NOTE: tON , tOFF TIME INDEPENDENT OF VSUPPLY Overcurrent Retry Duty Cycle vs. Timing Capacitance tON = 5mS VSUPPLY = 12V HIGH SIDE 0.0 5.0 10.0 15.0 20.0 25.0 0.1 1 10 100 1000 10000 RETRY DUTY CYCLE (%) C TL (pF) tON = 5mS VSUPPLY = 12V Overcurrent Retry Duty Cycle vs. Timing Capacitance LOW SIDE 100 0 5 10 15 20 25 IIN (mA) VIN (V) Input Current vs. Input Voltage VSUPPLY = 12V -60 -30 0 30 60 90 120 150 VOLTAGE (mV) TEMPERATURE ( °C) Sense Threshold vs. Temperature

September 1999 183 MIC5022 MIC5022 Micrel Input 0V TTL (H) 50mVSense H+, H– Differential Gate H Fault 15V (max.) Off On 5µs 20µs Enable 0V TTL (H) 0VGate L 15V (max.) 50mVSense L+, L– Differential 0V Input 0V TTL (H) Source 50mVSense H+, H– Differential Gate H Fault 15V (max.) Off On 5µs Enable 0V TTL (H) 0VGate L 15V (max.) 50mVSense L+, L– Differential 0V Timing Diagram 1. Normal Operation Input 0V TTL (H) Source 50mVSense H+, H– Differential Gate H Fault 15V (max.) Off On 0VGate L 15V (max.) 50mVSense L+, L– Differential 0V Enable 0V TTL (H) Timing Diagram 2. Overcurrent Fault with Retry Timing Diagram 3. Overcurrent Fault with Maintained Off

Refer to the MIC5022 block diagram. connected to GATE H turning the high-side MOSFET on. off and the low-side MOSFET turned on. resistor insures that the MIC5022 is enabled if the pin is open. low-side MOSFETs by limiting the gate to source voltage. voltage by supplying a small current as needed.

  1. This allows CINT and the optional capacitor

Figure 1. Basic Full-Bridge Circuit

September 1999 185 MIC5022 MIC5022 Micrel Applications Information The MIC5022 MOSFET driver is designed for half-bridge switching applications where overcurrent limiting and high speed are required. The MIC5022 can control MOSFETs that switch voltages up to 36V. The MIC5022 functionally includes the MIC5020 and MIC5021 with additional circuitry to coordinate the operation of the high and low-side drivers. Since most output considerations are similar, refer to the MIC5020 and MIC5021 data sheets for additional applications information. Supply Voltage The MIC5022’s supply input (V DD ) is rated up to 36V. The supply voltage must be equal to or greater than the voltage applied to the drain of the external N-channel MOSFET. A 16V minimum supply is recommended to produce continu- ous on-state, gate drive voltage for standard MOSFETs (10V nominal gate enhancement). When the driver is powered from a 12V to 16V supply, a logic- level MOSFET is recommended (5V nominal gate enhance- ment). PWM operation may produce satisfactory gate enhancement at lower supply voltages. This occurs when fast switching repetition makes the boost capacitor a more significant voltage supply than the internal charge pump. Overcurrent Limiting Separate high and low-side 50mV comparators are provided for current sensing. The low level trip point minimizes I losses when a power resistor is used for current sensing. The adjustable retry feature can be used to handle loads with high initial currents, such as lamps or heating elements, and can be adjusted from the C T connection. C T to ground causes maintained gate drive shutdown follow- ing an overcurrent condition. C T open, or a capacitor to ground, causes automatic retry. The default duty cycle (CT open) is approximately 20% (the high side is slightly greater than the low side). Refer to the typical characteristics when selecting a capacitor for a re- duced duty cycle. C T through a pull-up resistor to VDD increases the duty cycle. Increasing the duty cycle increases the power dissipation in the load and MOSFET under a “fault” condition. Circuits may become unstable at a duty cycle of about 75% or higher, depending on conditions. Caution: The MIC5022 may be damaged if the voltage applied to CT exceeds the absolute maximum voltage rating. Boost Capacitor Selection For 12V to 20V operation, the boost capacitor should be 0.01mF; and for 12V to 36V operation, the boost capacitor should be 2.7nF; both connected between VBOOST and the MOSFET source. The preferred configuration for 20V to 36V operation is a 0.1mF capacitor connected between V BOOST and VDD . Refer to the MIC5021 data sheet for examples. Do not connect capacitors between VBOOST and the MOSFET source and between VBOOST and VDD at the same time. Larger capacitors than specified may damage the MIC5022. Circuits Without Current Sensing Current sensing may be omitted by connecting the high-side SENSE + and SENSE – pins to the source of the MOSFET or the supply and the low-side SENSE + and SENSE – pins to ground. Do not connect the high-side sense pins to ground. Inductive Load Precautions Circuits controlling inductive loads require precautions when controlled by the MIC5022. Wire wound resistors, which are sometimes used to simulate other loads, can also show significant inductive properties. Sense Pin Considerations The sense pins of the MIC5022 are sensitive to negative voltages. If a voltage spike is too negative (below approxi- mately –0.5V), current will be drawn from functional sections of the IC resulting in unpredictable circuit behavior or dam- age. Resistors and Schottky diodes may be used to protect the sense pins from the negative spikes. Refer to the MIC5021 data sheet for details. High-Side Sensing For the high-side driver, sensing the current on the supply side of the high-side MOSFET locates the SENSE pins away from the inductive spike. Refer to the MIC5021 data sheet for details. Low-Temperature Operation As the temperature of the MIC5022AJB (extended tempera- ture range version—no longer available) approaches –55°C, the driver’s off-state, gate-output offset from ground in- creases. If the operating environment of the MIC5022AJB includes low temperatures (–40°C to –55°C), add an external 2.2MW resistor from gate-to-source or from gate-to-ground. This assures that the driver’s gate-to-source voltage is far below the external MOSFET’s gate threshold voltage, forcing the MOSFET fully off. Refer to the MIC5020 and MIC5021 data sheets for examples. The gate-to-source configuration is appropriate for resistive and inductive loads. This also causes the smallest decrease in gate output voltage. The gate-to-ground configuration is appropriate for resistive, inductive, or capacitive loads. This configuration will de- crease the gate output voltage slightly more than the gate-to- source configuration. Full-Bridge Motor Control An application for two MIC5022s is the full-bridge motor control circuit. Two high or two low-side sense inputs may be used for overcurrent detection. (Low-side sensing is shown in Fig- ure 2). Sensing at four locations is usually unnecessary. When switching inductive loads, such as motors, it is desir- able to place the high-side sense inputs on the supply side of the MOSFETs. The helps prevent the inductive spikes that occur upon load shutoff from affecting the sense inputs.