MIC5020_05 Datasheet, PDF (2/8 Pages) Micrel Semiconductor – Current-Sensing Low-Side MOSFET Driver

MIC5020
Pin Configuration
Block Diagram
1 V_DD Gate 8
2 Input Sense- 7
3 Fault Sense+ 6
4 C_T
Gnd 5
SOIC Package
(M)
6V Internal Regulator
I₁
C_INT
2I₁
Fault
Normal
Q1
C_T
Fault
Sense+
Sense-
50mV
Input
↑ _ONE-
↓ ^SHOT
10I₂
ON
OFF _6V
I₂
V_DD
Gate
Micrel, Inc.
Transistor Count: 82
Pin Description
Pin Number
1
2
3
4
Pin Name
V_DD
Input
Fault
C_T
5
Gnd
6
Sense +
7
Sense –
8
Gate
Pin Function
Supply: +11V to +50V. Decouple with ≥ 10µF capacitor.
TTL Compatible Input: Logic high turns the external MOSFET on. An internal
pull-down returns an open pin to logic low.
Overcurrent Fault Indicator: When the sense voltage exceeds threshold,
open collector output is open circuit for 5µs (t_G(ON)), then pulled low for
t_G(OFF). t_G(OFF) is adjustable from C_T.
Retry Timing Capacitor: Controls the off time (t_G(OFF)) of the overcurrent
retry cycle. (Duty cycle adjustment.)
• Open = 20% duty cycle.
• Capacitor to Ground = approx. 20% to <1% duty cycle.
• Pull-Up resistor = approx. 20% to approx. 75% duty cycle.
• Ground = maintained shutdown upon overcurrent condition.
Circuit Ground
Current Sense Comparator (+) Input: Connect to high side of sense resistor
or current sensing MOSFET sense lead. A built-in offset in conjunction with
R_SENSE sets the load overcurrent trip point.
Current Sense Comparator (–) Input: Connect to the low side of the sense
resistor (usually power ground).
Gate Drive: Drives the gate of an external power MOSFET. Also limits V_GS
to 15V max. to prevent Gate to Source damage. Will sink and source
current.
MIC5020
2
July 2005