HV9911NG 查看數據表（PDF） - Supertex Inc

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HV9911NG

Switch-mode LED Driver IC with High Current Accuracy

Supertex Inc 

Functional Block Diagram

HV9911

VIN

Linear Regulator

Vbg

REF

VDD

CLIM

_

SS

+

Blanking

100ns

CS

+

_

1:2

ramp

SC

FDBK

IREF

COMP

SS

_ Gm

13R

+

R

2

POR

GATE

R

Q

FAULT

S

+

_

R POR

Q

QS

SS

Vbg

OVP

One Shot

SYNC

RT

Functional Description

PWMD

GND

Power Topology

Continuous mode buck and boost converters are ideal as

LED drivers, as they can achieve high efficiencies greater

than 90%. The HV9911 is a switch-mode converter LED

driver designed to control a continuous conduction mode

buck or boost in a constant frequency (or constant off-time)

mode. The IC includes an internal linear regulator, which

operates from input voltages of 9V to 250V eliminating the

need for an external power supply for the IC. The IC includes

features typically required in LED drivers like open LED

protection, output short circuit protection, linear and PWM

dimming, programmable input current limiting and accurate

control of the LED current. A high current gate drive output

enables the controller to be used in high power converters.

Linear Regulator

external circuits connected at the VDD and VREF pins. This

linear regulator can be turned off by overdriving the VDD pin

using an external bootstrap circuit at voltages higher than

8.25V (up to 12V). The input voltage range of the IC can be

increased to 450V by putting a 200V zener in series with the

IC at the VIN pin.

Although this linear regulator can power the IC by itself, at

higher input voltages and/or higher operating temperatures,

it might be necessary to supply power using an external

bootstrap circuit as the excessive power dissipation in the IC

might cause the IC to fail. This would also result in improved

efficiencies for the overall circuit. Dropping the input voltage

across an external zener diode would also help to divert the

power dissipation away from the IC.

The built in linear regulator operates from input voltages of

9V to 250V and provides a 7.75V voltage at the VDD pin. This

7.75V is used to power the IC and also provide the power to

The VDD pin of the IC should be bypassed with at least a

0.1µF, low ESR capacitor.

NR011206

6

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