HV9931
Pin Description
Pin # Pin Name Description
1
VIN
This pin is the input of a high voltage regulator.
2, 7
CS1, CS2
These pins are used to sense the input and output currents of the converter. They are the
inverting inputs of the internal comparators.
3
GND
Ground return for all the internal circuitry. This pin must be electrically connected to the ground
of the power train.
4
GATE This pin is the output gate driver for an external N-channel power MOSFET.
When this pin is pulled to GND, switching of the HV9931 is disabled. When the PWMD pin
5
PWMD is released, or external TTL high level is applied to it, switching will resume. This feature is
provided for applications that require PWM dimming of the LED lamp.
6
VDD
This is a power supply pin for all internal circuits. It must be bypassed with a low ESR capacitor
to GND.
8
RT
Oscillator control. A resistor connected between this pin and GND sets the PWM frequency. A
resistor connected between this pin and GATE sets the PWM off-time.
7