DocID028720 Rev 1

15/19

HVLED002

Application information

19

5.7

Typical application

The HVLED002 device can be used as a secondary side step-down current regulator in the

multiple staged LED driver - see Figure 23. It is easy to configure the device to drive an

inverse (or modified) buck topology based on the fixed off-time (FOT) algorithm.

The MOSFET remains on until the current sense threshold is reached; during the on time,

the oscillator remains reset to ground. The current sense threshold is set by the saturation

of the E/A to MAXCS to guarantee the higher precision as possible.

The MOSFET is then turned off and the oscillator is released: the resulting off time is fixed

by the charging of the CT by RT, connected to VREF.

An optional auxiliary microcontroller, supplied by VREF itself can be used to dim the LED

current according to the information sent to the application by a remote controller.

Figure 23. Typical application

1. Optional for better performances.

VIN

D

Q1

L

RS

RT/CT

1

2

3

4

7

6

5

8

OUTPUT

GROUND

HVLED002

Isense

VFB

COMP

VREF

Vi

Vaux

μC

GND

VDD

GPIO

Osc. reset

Dimming

User interface