HV9989

DS20005296B-page 8

 2014 Microchip Technology Inc.

24

OVP3

Provides the over voltage protection for the converter. When the voltage at this pin

exceeds 5V, channel 3 of the HV9989 is turned off. The fault is reset by re-enabling the

IC using the EN pin.

25

REF3

The voltage at this pin sets the output current level for channel 3. Recommended voltage

range for this pin is 0V-1.25V.

26

FDBK3

Provides output current feedback for channel 3 by using a current sense resistor.

27

COMP3

Stable closed loop control can be accomplished by connecting a compensation network

between the COMP pin and its GND.

28

CS3

Used to sense the source current of the external power FET used with channel 3. It

includes a built-in 210 ns (min) blanking timer.

29

FLT3

Used to drive external disconnect switches. The disconnect switches are used to protect

the LEDs in case of fault conditions and also help to provide excellent PWM dimming

response by disconnecting and reconnecting the LEDs from the output capacitor during

PWM dimming.

30

VDD3

Power supply pin for channel 3. It can either be connected to the VDD pin or supplied

with an external power supply. It must be bypassed with a low ESR capacitor to their

respective GND3 (at least 0.1 μF). All VDD pins (VDD, VDD1-3) must be connected

together externally.

31

GATE3

Output gate driver for the external N-channel power MOSFET.

32

GND3

Ground return for channel 3. It is recommended that all the GNDs of the IC be connected

together in a STAR connection at the input GND terminal to ensure best performance.

33

VDD2

Power supply pin for channel 2. It can either be connected to the VDD pin or supplied

with an external power supply. It must be bypassed with a low ESR capacitor to their

respective GND2 (at least 0.1 μF). All VDD pins (VDD, VDD1-3) must be connected

together externally.

34

GND2

Ground return for channel 2. It is recommended that all the GNDs of the IC be connected

together in a STAR connection at the input GND terminal to ensure best performance.

35

GATE2

Output gate driver for the external N-channel power MOSFET.

36

FLT2

Used to drive external disconnect switches. The disconnect switches are used to protect

the LEDs in case of fault conditions and also help to provide excellent PWM dimming

response by disconnecting and reconnecting the LEDs from the output capacitor during

PWM dimming.

37

CS2

Used to sense the source current of the external power FET used with channel 2. It

includes a built-in 210 ns (min) blanking timer.

38

FDBK2

Provides output current feedback for channel 2 by using a current sense resistor.

39

GND1

Ground return for channel 1. It is recommended that all the GNDs of the IC be connected

together in a STAR connection at the input GND terminal to ensure best performance.

40

GATE1

Output gate driver for the external N-channel power MOSFET.

TABLE 2-1:

PIN DESCRIPTION (CONTINUED) (SHEET 2 OF 2)

Pin #

Name

Description