HT2273

1/10

Current Mode PWM Controller

www.hotchip.com.cn

Ver1.0

GENERAL DESCRIPTION

HT2273 is a high performance current mode PWM

controller, optimized for low power power switch

equipment.

For lower the standby power and higher RoHS

compliant, the IC offers a Burst Mode control

feature and ultra-low start-up current and operating

current, that is, at the condition of no load or light

load, HT2273 can reduce the switch frequency

linearly which minimize the switching power loss;

the ultra-low startup current and operating current

make a reliable power for startup design, and also

large resistor can be used in the startup circuit to

improve switching efficiency. The internal

synchronous slope compensation

circuit

reduces

the

possible subharmonic oscillation at

high PWM duty cycle output. Leading-edge

blanking on current sense(CS) input removes the

signal glitch due to snubber diode circuit reverse

recovery and thus greatly reduces the external

component count and system cost in the design.

HT2273 offers comprehensive protection coverage

with automatic self-recovery feature, including

cycle

by cycle over current protection (OCP), over

load protection (OLP),VCC Clamp, under voltage

lockout (UVLO), OTP and OVP shut down latch.

The gate-driven output is clamped to maximum

12V to protect the internal MOSFET.

Excellent EMI performance is achieved by using the

soft-switching and frequency jittering at the

totem-pole-gate-drive output. The tone energy at

below 20KHZ is minimized in the design and

audio noise is eliminat- ed during operation. The

HT2273 is the ideal substitute of the linear power

supply or

the

RCC-mod e power, for a better

performance of the whole switch power system and

a lower cost.

HT2273 is available in SOT23-6 package.

FEATURES

◆ Burst Mode Control

◆ 5uA ultra-low startup current

◆ 1.8mA Low operating current

◆ Built-in Leading-edge blanking

◆ Built-in synchronous slope compensation

circuit

◆ Built-in Soft-Start

◆ 65kHz fixed swith frequency

◆ Cycle by cycle over current protection (OCP)

◆ VCC over voltage clamp & under voltage

lockout( UVLO)

◆ Over load protection (OLP)

◆ OTP and OVP shut down latch

◆ Maximum Gate output voltage clamped at 12V

◆ Frequency jittering

◆ Adjustable OVP through external Zener

APPLICATIONS

Universal switch power supply equipment and

offline AC/DC flyback power converter Power

Adapter