Service manual

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In single lamp application, connect this pin to LI2 pin.

3 LI2 I

Lamp current feedback 2. The function of this pin is same as LI1. In

single lamp application, connect this pin to LI1. In multi-lamp application,

this pin is used for lamp current feedback which is out-of-phase of LI1.

4 COMP I

Feedback Compensation Node. Connect a compensation capacitor from

this pin to GND. This pin is also used for IC enable control. A logic low

(below 0.5V) input turns off the IC. The enable logic input signal should

have open collector (OC) structure.

5 FT I

Fault Indicator. Connect a capacitor from this pin to GND to program the

open lamp and short lamp protection delay time. When the voltage on

this pin reaches 1.2V, the IC will shutdown until it is enabled again.

6 FSET I

Switching Frequency Set. Connect a resistor from this pin to GND. This

resistor sets the operating frequency of the MP1009.

7 BOSC I

Burst Repetition Rate Setting. Connect a resistor and a capacitor from

this pin to GND. If the burst dimming is to be controlled by an external

logic signal, connect BOSC to VCC and apply the logic signal to the

DBRT pin.

8 DBRT I

Burst-Mode (Digital) Brightness Control Input. The voltage range of 0V to

1.2V at DBRT linearly sets the burst-mode duty cycle from minimum to

100%. The minimum burst dimming duty can be programmed by BOSC

resistor and capacitor. If burst dimming is not used, connect DBRT to

VCC.

9 VIN I

Input Power Rail. Decouple this pin to GND with >1μF ceramic capacitor.

It is desirable to add a 10 resistor between VIN pin and the input bus.

10 BT O

Output Bootstrap. BT provides gate driver bias for the high-side

MOSFET. Connect a capacitor from BT to SW.

11 TG O

High-Side MOSFET Gate Output. Connect TG to the gate of the

high-side, external power MOSFET.

12 SW O

Bridge Output. Connect SW to the source of the high-side MOSFET and

the drain of the low-side MOSFET.

13 VCC O

Voltage Rail Output. VCC provides power supply for the low-side gate

driver and the internal control circuitry. Bypass VCC to GND with a

ceramic capacitor.

14 BG O

Low-Side MOSFET Gate Output. Connect BG to the gate of the low-side

MOSFET.

15 GND IC ground

16 OV1 I

Open lamp voltage feedback input. The function of this pin is same as

OV2

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