LT1910

LT1910 - Protected High Side MOSFET Driver

Document overview

• Manufacturer or author: Linear Technology Corporation
• PDF pages: 14

Technical content

1910fcFor more information www.linear .com/L T1910 TYPICAL APPLICATION

DESCRIPTION

The LT®1910 is a high side gate driver that allows the use of low cost N-channel power MOSFETs for high side switching applications. It contains a completely self-contained charge pump to fully enhance an N-channel MOSFET switch with no external components. When the internal drain comparator senses that the switch current has exceeded the preset level, the switch is turned off and a fault flag is asserted. The switch remains off for a period of time set by an external timing capacitor and then automatically attempts to restart. If the fault still exists, this cycle repeats until the fault is removed, thus protecting the MOSFET . The fault flag becomes inactive once the switch restarts successfully. The L T1910 has been specifically designed for harsh operating environments such as industrial, avionics and automotive applications where poor supply regulation and/ or transients may be present. The device will not sustain damage from supply transients of –15V to 60V . The L T1910 is available in the SO-8 package. Fault Protected High Side Switch L, L T , L TC, L TM, Linear Technology and the Linear logo are registered trademarks and PowerPath and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.

FEATURES

APPLICATIONS

n 8V to 48V Power Supply Range n Protected from –15V to 60V Supply T ransients n Short-Circuit Protected n Automatic Restart Timer n Open-Collector Fault Flag n Fully Enhances N-Channel MOSFET Switches n Programmable Current Limit, Delay Time and Autorestart Period n Voltage Limited Gate Drive n Defaults to Off State with Open Input n Available in SO-8 Package n Industrial Control n Avionics Systems n Automotive Switches n Stepper Motor and DC Motor Control n Electronic Circuit Breaker Switch Drop vs Load Current FAUL T IN TIMER V SENSE GATE L T19105.1k 24V5V FAUL T OUTPUT OFF ON GND IRFZ34

1910 TA01

10µF 50V0.1µF 0.01/uni03A9 LOAD LOAD CURRENT (A) TOTAL DROP (V) 0.30 0.40 0.50

1910 TA02

0.20 0.10 0.25 0.35 0.45 0.15 0.05 1 2 3 5

1910fc For more information www.linear .com/L T1910 Operating Temperature Range (Note 2) (Note 1) TOP VIEW NC SENSE GATE GND TIMER FAULT IN S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 125°C, θJA = 150°C/W ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE L T1910ES8#PBF L T1910ES8#TRPBF 1910 8-Lead Plastic SO –40°C to 85°C L T1910IS8#PBF L T1910IS8#TRPBF 1910 8-Lead Plastic SO –40°C to 125°C LEAD BASED FINISH TAPE AND REEL PART MARKING PACKAGE DESCRIPTION TEMPERATURE RANGE L T1910ES8 L T1910ES8#TR 1910 8-Lead Plastic SO –40°C to 85°C L T1910IS8 L T1910IS8#TR 1910 8-Lead Plastic SO –40°C to 125°C Consult L TC Marketing for parts specified with wider operating temperature ranges. For more information on lead free part marking, go to: http://www.linear .com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear .com/tapeandreel/ PIN CONFIGURATIONABSOLUTE MAXIMUM RATINGS ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. V+ = 12V to 48V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS IS Supply Current (Off State) V+ = 48V , VIN = 0.8V 1.2 1.9 2.5 mA ∆IS(ON) Delta Supply Current (On State) VIN = 2V , Measure Increase in IS 0.8 1.2 mA VINH Input High Voltage E-Grade I-Grade l l 3.5 V V VINL Input Low Voltage E-Grade I-Grade l l 0.8 0.7 V V I IN Input Current VIN = 2V VIN = 5V l l 110 185 µA µA C IN Input Capacitance (Note 3) 5 pF VT(TH) Timer Threshold Voltage VIN = 2V , Adjust VT l 2.6 2.9 3.2 V VT(CL) Timer Clamp Voltage VIN = 0.8V 3.2 3.5 3.8 V IT Timer Charge Current VIN = VT = 2V 9 14 20 µA VSENSE Drain-Sense Threshold Voltage Temperature Coefficient (Note 3) 50 65 0.33 80 mV %/°C

1910fcFor more information www.linear .com/L T1910

ELECTRICAL CHARACTERISTICS

Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. Note 2: The L T1910E is guaranteed to meet performance specifications from 0°C to 70°C. Specifications over the –40°C to 85°C operating temperature range are assured by design, characterization and correlation The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. V+ = 12V to 48V unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS ISENSE Drain Sense Input Current V+ = 48V , VSENSE = 65mV 0.5 1.5 µA VGATE – V+ Gate Voltage Above Supply V+ = 8V V+ = 12V l 4.5 8.5 V V V + = 24V E-Grade I-Grade l l V V V + = 48V E-Grade I-Grade l l V V V F(TH) FAUL T Output High Threshold Voltage FAUL T Output Low Threshold Voltage V IN = 2V , IF = 1mA, Adjust VT 3.1 3.0 3.4 3.3 3.7 3.6 V V V FOL FAUL T Output Low Voltage IF = 1mA l 0.07 0.4 V tON Turn-On Time V+ = 24V , VGATE = 32V , CGATE = 1nF 100 220 400 µs tOFF Turn-Off Time V+ = 24V , VGATE = 2V , CGATE = 1nF 25 100 µs tOFF(CL) Current Limit Turn-Off Time V+ = 24V , (V+ – VSENSE)→0.1V , CGATE = 1nF 20 50 µs with statistical process controls. The L T1910I is guaranteed to meet performance specifications over the full –40°C to 125°C operating temperature range. Note 3: Guaranteed but not tested.TYPICAL PERFORMANCE CHARACTERISTICS Supply Current vs Supply Voltage Supply Current vs Temperature Input Voltage vs Temperature SUPPL Y VOL TAGE (V) SUPPL Y CURRENT (mA) 2.4 2.8 3.2 3.6

1910 G01

2.0 1.6 2.2 2.6 3.0 3.4 1.8 1.4 1.2 10 20 30 50 ON STATE OFF STATE TA = 25°C TEMPERATURE (°C) –50 SUPPLY CURRENT (mA) 1.0 2.0 3.0 2.5 –25 0 25 50

1910 G02

4.0 5.0 0.5 1.5 3.5 4.5 125 100 V+ = 48V ON STATE OFF STATE TEMPERATURE (°C) –50 INPUT VOLTAGE (V) 1.0 1.2 1.4 1.6 2.0 –25 0 25 50

1910 G03

1.8 0.8 VINH VINL

1910fc For more information www.linear .com/L T1910 TYPICAL PERFORMANCE CHARACTERISTICS Timer Charge Current vs Temperature Drain Sense Threshold Voltage vs Temperature MOSFET Gate Voltage Above V (VGATE – V+) vs Supply Voltage MOSFET Gate Drive Current vs V GATE – V+ Fault Threshold Voltage vs Temperature Fault Output Low Voltage vs Temperature Input Current vs Temperature Timer Threshold Voltage vs Temperature Timer Clamp Voltage vs Temperature TEMPERATURE (°C) –50 INPUT CURRENT (µA) 120 –25 0 25 50

1910 G04

VIN = 5V VIN = 2V TEMPERATURE (°C) –50 TIMER THRESHOLD VOLTAGE (V)2.7 2.8 2.9 3.0 3.2 –25 0 25 50

1910 G05

3.1 2.6 VIN = 2V TEMPERATURE (°C) –50 TIMER CLAMP VOLTAGE (V) 3.3 3.4 3.5 3.6 3.8 –25 0 25 50

1910 G06

3.7 3.2 VIN ≤ 0.8V TEMPERATURE (°C) –50 TIMER CHARGE CURRENT (µA)10 –25 0 25 50

1910 G07

VIN = VT = 2V TEMPERATURE (°C) –50 DRAIN SENSE THRESHOLD VOLTAGE (mV) –25 0 25 50

1910 G08

V+ = 24V SUPPLY VOLTAGE (V) MOSFET GATE VOLTAGE ABOVE V+ (VGATE – V+) (V)16 LTC1266  F04 10 20 30 50355 15 25 45 TA = 125°C TA = –40°C TA = 25°C VGATE – V+ (V) 0 2 4 MOSFET GATE DRIVE CURRENT (µA) 100 6 8 10 12 14 16

1910 G10

0.1 V+ = 8V V+ = 12V V+ ≥ 24V TA = 25°C TEMPERATURE (°C) –50 FAULT OUTPUT LOW VOLTAGE (V) 0.04 0.08 0.12 0.10 –25 0 25 50

1910 G012

0.16 0.20 0.02 0.06 0.14 0.18 125 100 IF = 1mA TEMPERATURE (°C) –50 FAULT THRESHOLD VOLTAGE (V) 3.2 3.3 3.4 3.5 3.7 –25 0 25 50

1910 G11

3.6 3.0 3.1 VIN = 2V IF = 1mA FAULT HIGH THRESHOLD FAULT LOW THRESHOLD

1910fcFor more information www.linear .com/L T1910 TYPICAL PERFORMANCE CHARACTERISTICS Turn-On Time vs Temperature Turn-Off Time vs Temperature Automatic Restart Period vs Temperature TEMPERATURE (°C) –50 TURN-ON TIME (µs) 150 200 250 300 400 –25 0 25 50

1910 G13

V+ = 24V VGATE = 32V CGATE = 1nF TEMPERATURE (°C) –50 TURN-OFF TIME (µs) –25 0 25 50

1910 G014

V+ = 24V VGATE = 2V CGATE = 1nF NORMAL CURRENT LIMIT TEMPERATURE (°C) –30 100 1000 –10 10 30 50 90 70

1910 G15

AUTOMATIC RESTART PERIOD (ms) –50 130 110 V+ = 24V CT = 3.3µF CT = 0.33µF CT = 0.1µF CT = 1µF PIN FUNCTIONS GND (Pin 1): Common Ground. TIMER (Pin 2): A timing capacitor , CT , from the TIMER pin to ground sets the restart time following overcurrent detection. Upon detection of an overcurrent condition, CT is rapidly discharged to less than 1V and then recharged by a 14µA nominal current source back to the 2.9V timer threshold, whereupon the restart is attempted. Whenever TIMER pulls below 2.9V , the GATE pin pulls low to turn off the external switch. This cycle repeats until the overcurrent condition goes away and the switch restarts successfully. During normal operation the pin clamps at 3.5V nominal. FAUL T (Pin 3): The FAUL T pin monitors the TIMER pin voltage and indicates the overcurrent condition. Whenever the TIMER pin is pulled below 3.3V at the onset of a cur- rent limit condition, the FAUL T pin pulls active LOW . The FAUL T pin resets HIGH immediately when the TIMER pin ramps above 3.4V during autorestart. The FAUL T pin is an open-collector output, thus requiring an external pull-up resistor and is intended for logic interface. The resistor should be selected with a maximum of 1mA pull-up at low status. IN (Pin 4): The IN pin threshold is TTL/CMOS compatible and has approximately 200mV of hysteresis. When the IN pin is pulled active HIGH above 2V , an internal charge pump is activated to pull up the GATE pin. The IN pin can be pulled as high as 15V regardless of whether the sup - ply is on or off. If the IN pin is left open, an internal 75k pull-down resistor pulls the pin below 0.8V to ensure that the GATE pin is inactive LOW . GATE (Pin 5): The GATE pin drives the power MOSFET gate. When the IN pin is greater than 2V , the GATE pin is pumped approximately 12V above the supply. It has rela- tively high impedance (the equivalence of a few hundred kΩ) when pumped above the rail. Care should be taken to minimize any loading by parasitic resistance to ground or supply. The GATE pin pulls LOW when the TIMER pin falls below 2.9V . SENSE (Pin 6): The SENSE pin connects to the input of a supply-referenced comparator with a 65mV nominal offset. When the SENSE pin is taken more than 65mV below supply, the MOSFET gate is driven LOW and the timing capacitor is discharged. The SENSE pin threshold has a 0.33%/°C temperature coefficient (TC), which closely matches the TC of the drain-sense resistor formed from the copper trace of the PCB. For loads requiring high inrush current, an RC timing delay can be added between the drain-sense resistor and the SENSE pin to ensure that the current-sense comparator

1910fc For more information www.linear .com/L T1910 PIN FUNCTIONS BLOCK DIAGRAM does not false trigger during start-up (see Applications Information). A maximum of 10kΩ can be inserted between a drain-sense resistor and the SENSE pin. If current sensing is not required, the SENSE pin is tied to supply. V + (Pin 8): In addition to providing the operating cur - rent for the L T1910, the V+ pin also serves as the Kelvin connection for the current-sense comparator . The V+ pin must be connected to the positive side of the drain-sense resistor for proper current-sensing operation. + +– +3.3V TIMER IN 14µA 2.9V 1.4V 75k 75k FAULT 1.4V 250/uni03A9 1910 BD GATE SENSE 65mV OSCILLATOR AND CHARGE PUMP OPERATION(Refer to the Block Diagram) The L T1910 GATE pin has two states, off and on. In the off state it is held LOW , while in the on state it is pumped to 12V above the supply by a self-contained 750kHz charge pump. The off state is activated when either the IN pin is below 0.8V or the TIMER pin is below 2.9V . Conversely, for the on state to be activated, the IN pin must be above 2V and the TIMER pin must be above 2.9V . The IN pin has approximately 200mV of hysteresis. If it is left open, the IN pin is held LOW by a 75k resistor . Under normal conditions, the TIMER pin is held a diode drop above 2.9V by a 14µA pull-up current source. Thus the TIMER pin automatically reverts the GATE pin to the on state if the IN pin is above 2V . The SENSE pin normally connects to the drain of the power MOSFET , which returns through a low value drain-sense resistor to supply. In order for the sense comparator to accurately sense the MOSFET drain current, the V + pin must be connected directly to the positive side of the drain-sense resistor . When the GATE pin is on and the MOSFET drain current exceeds the level required to gener- ate a 65mV drop across the drain-sense resistor , the sense comparator activates a pull-down NPN which rapidly pulls the TIMER pin below 2.9V . This in turn causes the timer comparator to override the IN pin and set the GATE pin to the off state, thus protecting the power MOSFET . When the TIMER pin is pulled below 3.3V , the fault comparator

pin LOW , indicating an overcurrent condition.

1910 F01

Figure 1. Timing Diagram prevent ground transients from damaging control logic. the off state (see Figure 2).

1910 F03

Figure 2. Isolating the Input Figure 3. Drain-Sense Configuration

generate large current transients at turn-on. unsuccessfully under an existing fault condition. across each inductive load normally serves this purpose. across it, resulting in high dissipation peaks. by controlling the ∂V/∂t on the gate.

1910 F04

1910 F05

Figure 4. Latch-Off Configuration (Autorestart Defeated) Figure 5. Control and Current Limit Delay

network ensure fast current limit turn-off. LOAD as fast as the gate is being pulled down. GS(MAX) from being exceeded.

1910 F06

Figure 6. Gate Drive Current vs Gate Voltage by the current limit delay network shown in Figure 5.

0.01 TRIP DELAY TIME (1 = RDCD)

1910 F07

Figure 7. Current Limit Delay Time drain-sense resistor made out of PC trace material.

1910fc For more information www.linear .com/L T1910 APPLICATIONS INFORMATION Low Voltage/Wide Supply Range Operation When the supply is less than 12V , the L T1910’s charge pump does not produce sufficient gate voltage to fully enhance the standard N-channel MOSFET . For these ap- plications, a logic-level MOSFET can be used to extend the operating supply down to 8V . If the MOSFET has a maximum V GS rating of 15V or greater , then the L T1910 can also operate up to a supply voltage of 60V (absolute maximum rating of the V + pin). Protecting Against Supply T ransients The L T1910 is 100% tested and guaranteed to be safe from damage with 60V applied between the V+ and GND pins. However , when this voltage is exceeded, even for a few microseconds, the result can be catastrophic. For this reason it is imperative that the L T1910 is not exposed to supply transients above 60V . A transient suppressor , such as Diodes Inc.’s SMAJ48A, should be added between the V + and GND pins for such applications. For proper current sense operation, the V+ pin is required to be connected to the positive side of the drain-sense resistor (see Drain-Sense Configuration). Therefore, the supply should be adequately decoupled at the node where the V + pin and drain sense resistor meet. Several hundred microfarads may be required when operating with a high current switch. When the operating voltage approaches the 60V absolute maximum rating of the L T1910, local supply decoupling between the V + and GND pins is highly recommended. An RC snubber with a transient suppressor are an absolute necessity. Note however that resistance should not be added in series with the V + pin because it will cause an error in the current-sense threshold. Low Side Driving Although the L T1910 is primarily targeted at high side (grounded load) switch applications, it can also be used for low side (supply connected load) switch applications. Figures 8a and 8b illustrate the L T1910 driving low side power MOSFETs. Because the L T1910 charge pump tries to pump the gate of the N-channel MOSFET above the supply, a clamp Zener is required to prevent the V GS (ab- solute maximum) of the MOSFET from being exceeded. The L T1910 gate drive is current limited for this purpose so that no resistance is needed between the GATE pin and Zener . Current sensing for protecting low side drivers can be done in several ways. In the Figure 8a circuit, the supply voltage for the load is assumed to be within the supply operating range of the L T1910. This allows the load to be returned to supply through current-sense resistor , R S, providing normal operation of the L T1910 protection circuitry. If the load cannot be returned to supply through R S, or the load supply voltage is higher than the L T1910 supply, the current sense must be moved to the source of the low side MOSFET . Figure 8b shows an approach to source sensing. An operational amplifier (must common mode to ground) is used to level shift the voltage across R S up to the drain- sense pin. This approach allows the use of a small sense resistor which could be made from PC trace material. The L T1910 restart timer functions the same as in the high side switch application.

1910fcFor more information www.linear .com/L T1910 FAUL T IN SENSE L T1910 5.1k 12V TO 48V FAUL T OUTPUT INPUT GND IRFZ44 15V 1N4744

1910 F08a

100µF 100V C T 1µF RS 0.01/uni03A9 (PTC) LOAD GATETIMER 5 FAUL T IN TIMER V SENSE GATE L T1910 5.1k FAUL T OUTPUT INPUT GND IRF63015V 1N4744

1910 F08b

10µF 50V CT 1µF RS 0.02/uni03A9 HV LOAD51/uni03A9 2N2222 8V TO 24V HV L T1006 51/uni03A9 Figure 8a. Low Side Driver with Load Current Sensing Figure 8b. Low Side Driver for Source Current Sensing APPLICATIONS INFORMATION

1910fc For more information www.linear .com/L T1910 .016 – .050 (0.406 – 1.270) .010 – .020 0°– 8° TYP .008 – .010 (0.203 – 0.254) SO8 REV G 0212 .053 – .069 (1.346 – 1.752) .014 – .019 (0.355 – 0.483) TYP .004 – .010 (0.101 – 0.254) .050 (1.270) BSC 1 2 3 4 .150 – .157 (3.810 – 3.988) NOTE 3 8 7 6 5 .189 – .197 (4.801 – 5.004) NOTE 3 .228 – .244 (5.791 – 6.197) .245 MIN .160 ±.005 RECOMMENDED SOLDER PAD LAYOUT .045 ±.005 .050 BSC .030 ±.005 TYP INCHES (MILLIMETERS) NOTE: 1. DIMENSIONS IN 2. DRAWING NOT TO SCALE 3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm) 4. PIN 1 CAN BE BEVEL EDGE OR A DIMPLE 8-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610 Rev G) PACKAGE DESCRIPTION Please refer to http://www.linear .com/designtools/packaging/ for the most recent package drawings.

1910fcFor more information www.linear .com/L T1910 Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However , no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.

REVISION HISTORY

REV DATE DESCRIPTION PAGE NUMBER B 7/14 Updated FAUL T pin description 5 C 6/15 Changed top mark 2 (Revision history begins at Rev B)

1910fc For more information www.linear .com/L T1910 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear .com/L T1910  LINEAR TECHNOLOGY CORPORATION 2009 LT 0615 REV C • PRINTED IN USA RELATED PARTS TYPICAL APPLICATION Protected 1A Automotive Solenoid Driver with Overvoltage Shutdown FAUL T IN TIMER V SENSE GATE L T1910 5.1k FAUL T OUTPUT INPUT POWER GROUND 8V TO 24V OPERATING 32V TO 60V SHUTDOWN GND MTD3055EL 24V SOLENOID

1910 TA03

10µF 100V C T 1µFR3 5.1k 1N4148 2N3904 R S 0.03/uni03A9 (PTC)+ 10k 30V 1N6011B PART NUMBER DESCRIPTION COMMENTS LT C

1153 Autoreset Electronic Circuit Breaker Programmable T rip Current, Fault Status Output

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