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MIC5031
Micrel
MIC5031
High-Speed High-Side MOSFET Driver Not Recommended for New Designs
General Description
The MIC5031 MOSFET driver is designed to switch an N-channel enhancement-type MOSFET from a TTL control signal in a high-side switch application. The MIC5031 provides overcurrent protection, can accommodate loads with high-inrush current, and is designed to survive automotive power disturbances. This driver is suitable for up to 30kHz PWM operation with 0% to 100% duty cycle. The MIC5031 is powered by the +4.5V to +30V load voltage. An external bootstrap capacitor and internal charge pump drive the gate output higher than the supply voltage. The bootstrap capacitor provides speed, while the charge pump can sustain the high gate output voltage continuously. The MIC5031 features a resistor programmable overcurrent shutdown (circuit breaker) function that monitors the voltage drop across the external MOSFET. A capacitor programmable shutdown delay allows a high-inrush current load to be energized without causing undesired shutdown. An openload detection feature is included and can be used by adding an external high-value resistor. The MIC5031 is protected against automotive load dump and reverse battery conditions. The driver is also protected from excessive power dissipation by an internal overtemperature shutdown circuit. An open-collector fault flag output indicates overcurrent, overtemperature, or open-load fault conditions.
Features
* +4.5V to +30V operation * Fast gate drive (rise time = 70ns, fall time = 50ns, with 1000pF load and 5V supply) * Overcurrent detection across MOSFET * Overcurrent shutdown delay * Charge pump for high-side dc applications * TTL compatible input * Overtemperature shutdown * Automotive load dump protection * Reverse battery protection * Open-collector fault flag * Near zero-current disable state
Applications
* * * * Automotive power switch Automotive PWM control Circuit breaker PWM circuits
Ordering Information
Part Number MIC5031BM Temperature Range -40C to +85C Package 16-lead SOIC
Typical Application
+4.5V to +30V 100F 100nF 10k 0.01F
Enable Disable On Off 4 3 10 8 11 9 5
51k MIC5031
7
VDD EN CTL CP1+ CP1- CP2+ CP2- GND
FLG RV G CB S RI CS DLY
1 14 16 12 13 15 6 2
Normal Fault
1k* IRF540 0.1F 100k
0.01F
0.01F
0.1F 50pF
12k* M
2N5822
15F
* Sets Overcurrent Trip to MOSFET VDS 102mV Optional Resistor for Open-Load Detection Optional Capacitor for Overcurrent Delay Optional Resistor and Capacitor for Power-up Sequence
High-Side Power Switch and Circuit Breaker
Micrel, Inc. * 1849 Fortune Drive * San Jose, CA 95131 * USA * tel + 1 (408) 944-0800 * fax + 1 (408) 944-0970 * http://www.micrel.com
August 1999
1
MIC5031
MIC5031
Micrel
Pin Configuration
FLG 1 DLY 2 CTL 3 EN 4 GND 5 CS 6 VDD 7 CP1- 8
16 G 15 RI 14 RV 13 S 12 CB 11 CP2+ 10 CP1+ 9 CP2-
16-lead SOIC (M)
Pin Description
Pin Number 1 2 3 Pin Name FLG DLY CTL Pin Function Fault Flag: (Output): Open-collector output sinks current upon overcurrent, open-load, or overtemperature detection. 10mA maximum load. Overcurrent Delay Time Capacitor: Optional. Capacitor to ground delays activation of overcurrent shutdown. Control (Input): TTL compatible on/off control input. Logic high drives the gate output above the supply voltage. Logic low forces the gate output near ground. Logic low also resets the overcurrent fault latch. Enable (Input): CMOS compatible input. Logic high enables the charge pump. Logic low disables the charge pump and draws near zero supply current. Ground: Power return. Internal Supply Storage Capacitor: 10F external capacitor to GND. Provides additional current to internal circuitry during switching transitions. Supply (Input): +4.5V to +30V supply. Charge Pump Capacitor #1: Refer to CP1+. Charge Pump Capacitor #2: Refer to CP2+. Charge Pump Capacitor #1: External 0.01F voltage tripler capacitor. Charge Pump Capacitor #2: External 0.01F voltage tripler capacitor. Bootstrap Capacitor: 0.1F capacitor to source for fastest rise time. Source: Source connection to external MOSFET. Reference Voltage Resistor: Resistor to VDD provides a reference voltage drop. A voltage drop across the external MOSFET that is greater than the voltage drop across the reference resistor indicates an overcurrent condition. (Refer to applications section) Zero temperature coefficient resistor recommended. Reference Current Resistor: Resistor to GND sets constant current value through RV resistor (Refer to applications section) and matches temperature compensation of RV resistor. Zero temperature coefficient resistor recommended. Gate (Output) : Gate connection to external MOSFET.
4
EN
5 6 7 8 9 10 11 12 13 14
GND CS VDD CP1- CP2- CP1+ CP2+ CB S RV
15
RI
16
G
MIC5031
2
August 1999
MIC5031
Micrel
Absolute Maximum Ratings
Supply Voltage (VDD) .................................................. +36V Enable Input Voltage (VEN) ......................................... +36V Control Input Voltage (VCTL) VDD 15V ..................................................................VDD VDD > 15V ............................................................... +15V Flag Output Voltage (VFLG) ......................................... +36V Reference Voltage Input (VRV) .................................... +36V Junction Temperature (TJ) ........................................ 150C
Operating Ratings
Supply Voltage (VDD) ................................... +4.5V to +30V Ambient Temperature Range (TA) A-temperature range ............................ -55C to +125C B-temperature range .............................. -40C to +85C Package Thermal Resistance (JA) SOIC ................................................................. 115C/W
Electrical Characteristics
VDD = 12V; CB = 0.1F, CP1 = CP2 = 0.01F; TA = 25C; unless noted Symbol IDD Parameter Supply current Condition VEN = 0V, VCTL = 0V VEN = 12V, VCTL = 0V VEN = 12V, VCTL = 5V IDDR VCTL VCTLH ICTL VEN IEN VIOS IRV tSHDL VG tDLR tR tDLF tF VOLTH TOT TOTH fCP VFLG
Note 1:
Min
Typ 0.3 1.0 0.72 -0.2 1.55
Max 3
Units A mA mA A V
Reverse voltage leakage current Control input voltage threshold Control input voltage hysteresis Control input current Enable input voltage threshold Enable input current Overcurrent comparator offset Current limit reference current Overcurrent shut down delay Gate drive voltage Gate turn-on delay Gate rise time Gate turnoff delay Gate fall time Open-load threshold voltage Overtemperature shut down Overtemp. shut down hysteresis Charge pump frequency Flag active voltage
Oscillator burst mode at VDD 5.2V.
VDD = -12V 0.2
-5
0.5 0.1 6 0.1
1.0 1
V A V A mV A s V ns ns ns ns V C C
1 5
RRI = 12.0k CDLY = 50pF VEN = 12V, VCTL = 5V VEN = 12V, CL = 1000p CL = 1000pF CL = 1000pF CL = 1000pF VEN = 12V, VCTL = 0V VEN = 12V, VCTL = 5V VEN = 12V, VCTL = 5V VDD = 5V, Note 1 open load error, IFLG = 2mA (sink)
97
100 16 25 420 90 300 50 6.3 140
103
10 190 0.2
kHz V
General Note: Devices are ESD protected; however, handling precautions are recommended.
August 1999
3
MIC5031
MIC5031
Micrel
Block Diagram
VSUPPLY C1 CP1- CP1+ C2 CP2- CP1+ VDD
Charge Pump CS Bias Regulator Oscillator Voltage Tripler Osc. Disable Gate Driver G Reset CTL
(TTL)
Gate Drive Regulator
CB C3
External N-Channel MOSFET
Open-Load Detect Resistor (Optional)
Logic Open-Load Detect
EN
(CMOS)
S Current Limit Delay Voltage Comp. RV R1
DLY
Overcurrent Delay Capacitor (Optional)
1.23V Bandgap Reference
Ref. Current Amp. Lockout Latch RI
C4 R2 FLAG
Overtemp. Detect MIC5031 GND
MIC5031 with External Components
MIC5031
4
Inductive Load
August 1999
MIC5031
Micrel
Current Sense Refer to the "Voltage Reference (Simplified)" diagram. The MIC5031 detects an overcurrent condition by comparing the voltage drop across the external MOSFET to a reference voltage drop created across R1. If VDS exceeds VR1, a comparator (not shown) shuts off the external MOSFET by way of the current limit delay, lockout latch, and logic. The bandgap reference, op amp and NPN create a constant voltage (1.23V) across R2. This results in a constant current, IR2, through R2. Ignoring a small amount of base current, the same current (IR2) flows through R1. R1 is selected to achieve the desired reference voltage drop, VR1. Refer to the applications section for formulas.
Supply
Functional Description
Refer to "Functional Diagram." The MIC5031 is a noninverting device. Applying a CMOS logic high signal to EN (enable input) activates the driver's internal circuitry. Applying a TTL logic high signal to CTL (control input) produces gate drive output. The G (gate) output is used to turn on an external N-channel MOSFET. Control CTL (control) is a TTL compatible input. The threshold is approximately 1.4V, independent of the supply voltage. The falling edge of a signal applied to CTL also resets the overcurrent lockout latch. Enable EN (enable) is a CMOS compatible input. EN enables or disables all internal circuitry. The enable threshold is approximately half the supply voltage. The MIC5031 supply current is near zero when the driver is disabled (low). See "Applications Information: Power-Up Sequence." Charge Pump The charge pump produces a voltage that is higher than the supply voltage. This higher voltage is required to drive the external N-channel MOSFET in high-side switch circuits. The charge pump consists of an oscillator and a voltage tripler. When the driver is enabled, the charge pump is switched on and off to regulate its output voltage. External capacitors C1 and C2 are required. The charge pump will not operate without these capacitors. Bootstrap Capacitor The external bootstrap capacitor is necessary to achieve the fastest gate rise times. The bootstrap capacitor (C3) supplies additional current at a higher voltage to the gate drive regulator as the MOSFET is switched on. When the MOSFET is off, the gate drive regulator voltage is applied to the boost capacitor . As the MOSFET turns on, the MOSFET source-to-ground voltage increases. The increasing source voltage is added to the voltage across the capacitor for a voltage doubling effect. Gate Drive Regulator The gate drive regulator manages the voltage from the bootstrap capacitor, the supply, and the charge pump. The gate drive regulator charges the bootstrap capacitor when the MOSFET is off and limits the voltage from the bootstrap capacitor as the MOSFET is switched on. It also performs skip-mode control by switching the charge pump on and off to regulate the gate drive output voltage. Gate Output When the MIC5031 is enabled and CTL is high, the gate driver steers regulated voltage to G (gate output). When CTL is low, the gate driver grounds G. This respectively charges or discharges the external MOSFET's gate, .
VR1 IR2 RV
R1
External N-Channel VDS MOSFET
RI IR2 1.23V R2
Voltage Reference (Simplified) An overcurrent condition also activates the fault flag output when the lockout latch is activated. Overcurrent-Shutdown Delay The overcurrent-shutdown delay circuit permits a delay between overcurrent detection and latch activation for highinrush current loads. The delay can be increased by adding capacitance from DLY to GND. Open-Load Detect The open load detect resistor is an external high-value pullup resistor that causes the source voltage of the external MOSFET to increase when the load is missing. The MIC5031 monitors the S-pin voltage only when the gate driver is off. If the voltage on the S-pin rises above the openload detect threshold, the fault flag is activated. Overtemperature Detect The overtemperature detect circuit switches the logic to turn the output off at approximately 140C. An overtemperature shutdown condition is restored to normal automatically When the device cools to about 130C (10C hysteresis). An overtemperature condition also activates the fault flag output. Fault Flag FLT (fault flag) is an open-collector NPN transistor. Fault is active (pulls collector near ground) upon overcurrent, openload, or overtemperature.
August 1999
5
Load
1.23V Bandgap Reference
MIC5031
MIC5031
Micrel Reference Current Resistor Resistor R2 sets the reference current. For most applications, a reference current of 100A is suggested.
R2 = R1 IR2
Applications Information
Power-Up Sequence The supply voltage (VDD) must be applied to VDD before EN is asserted. If EN is not required for the application, an RC network must be used to delay the voltage rise applied to EN with respect to VDD. See Figure 1.
+4.5V to +30V 100F 100nF MIC5031
7
where: R2 = reference current resistor () IR2 = reference current (A) [R2 = 12k for approximately 100A] Reference Voltage Resistor
0.01F
10k
On Off
VDD EN CTL CP1+ CP1- CP2+ CP2- GND
FLG RV G CB S RI CS DLY
1 14 16 12 13 15 6 2
4 3 10 8 11 9 5
IRF540 0.1F
0.01F
The reference voltage resistor value is calculated from the reference current and the reference voltage (overcurrent drop voltage).
V R1 = R1 IR2
0.01F
0.1F 15F
12k*
M
2N5822
where: R1 = reference voltage resistor () VR1 = reference voltage (V) [see above] IR2 = reference current (A) [see above] Overcurrent Delay Capacitor For lamp switching applications, the delay capacitor (CDLY) may be as high as several microfarads. Lamps often have an inrush current of 10x their steady-state operating current. In PWM applications, pay attention to the input frequency vs. the overcurrent delay. They can conflict with each other if not properly planned.
Figure 1. Enable Application Refer to "Typical Application" for controlling EN from opencollector or open-drain logic. The 10k resistor and 0.01F capacitor connected to VDD, GND, and EN keep EN low during power up before the open-collector or open-drain logic becomes active. The 10k resistor and 0.01F capacitor can be omitted if EN is held low by the external logic until VDD is powered. Overcurrent Detection Using the MOSFET manufacturer's data and the maximum allowable load current, determine the maximum drain-tosource voltage drop, VDS, that will occur across the external MOSFET in normal operation. This will also be the reference voltage and the overcurrent trip voltage, VR1. VR1 = maximum RDS(on) x maximum load current
Supply
VR1 IR2 RV
R1
External N-Channel VDS MOSFET
RI IR2 1.23V R2
Figure 2. Resistor Calculations
MIC5031
Load
1.23V Bandgap Reference
6
August 1999
MIC5031
Micrel
Package Information
PIN 1
0.157 (3.99) 0.150 (3.81)
DIMENSIONS: INCHES (MM)
0.020 (0.51) REF 0.050 (1.27) BSC
0.020 (0.51) 0.013 (0.33) 0.0098 (0.249) 0.0040 (0.102)
45 0-8 0.050 (1.27) 0.016 (0.40) 0.244 (6.20) 0.228 (5.79)
0.0648 (1.646) 0.0434 (1.102)
0.394 (10.00) 0.386 (9.80)
SEATING PLANE
16-Lead SOIC (M)
August 1999
7
MIC5031
MIC5031
Micrel
MICREL INC.
TEL
1849 FORTUNE DRIVE SAN JOSE, CA 95131
FAX
USA
+ 1 (408) 944-0800
+ 1 (408) 944-0970
WEB
http://www.micrel.com
This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc. (c) 1999 Micrel Incorporated
MIC5031
8
August 1999

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