HV9608 Datasheet, PDF (1/6 Pages) Supertex, Inc – Active Clamp Current-Mode PWM Controller

HV9608
Initial Release
Active Clamp Current-Mode PWM Controller
Features
Peak current-mode PWM Controller
Two complementary MOSFET drivers
Programmable deadtime between drivers
High current gate drivers for main and auxiliary outputs
Internal high voltage (12V to 250V) start-up regulator
Programmable V_IN undervoltage lockout and hysteresis
V_DD supply operation from 7.8V to 12V
Fixed frequency PWM operation from 25KHz to 800KHz
>50% duty cycle operation (up to 95%)
Programmable slope compensation
Programmable max duty-cycle/volt-second clamp
Capacitor programmable soft-start
Cycle-by-cycle current limiting
100ns current sense leading edge blanking
2 MHz error amplifier
Applications
Networking
Telecommunication Systems and Terminals
IEEE 802.3af PoE PD Devices
SANS, Servers & Workstations
High Efficiency Instrumentation Supplies
High Efficiency Supplies for Portable Equipment
Description
The HV9608 provides a single chip, optimized peak current
mode control solution for design of high performance PWM
converters using the active-clamp transformer flux reset.
Due to its programmable slope compensation feature, the
HV9608 allows operation beyond 50% duty cycle. Zero-
voltage switching can be accomplished through using the
programmable deadtime timers. The switching frequency
can be programmed from 25kHz to 800kHz using a single
resistor. The internal high voltage startup circuit can ensure
start-up from the input voltage from 12V to 250V. It can also
maintain the HV9608 in operation when the external
“bootstrap” power supply is not available. The startup
regulator is disconnected as soon as the HV9608 becomes
powered from the bootstrap winding. The HV9608 offers a
programmable soft start feature using a single external
capacitor. The cycle by cycle current limit feature can
protect the converter from overheating and damage by
limiting the output over current. The HV9608 will maintain
the cycle-by-cycle current limiting mode for a period of time
programmed by the soft start capacitor value. The HV9608
includes a single pin UVLO circuit that allows independent
accurate setting of both the turn-on and the turn-off
threshold voltage. A programmable volt-second clamp
reduces voltage stress of the switching devices. The
HV9608 is available in a space-saving TSSOP-16 package.
Typical Application Circuit
VIN
C_IN
R_VS
R1
R2
C1
HV9608
1 VIN
VDD 16
2 UVLO
3 REF
DT1 15
AGATE 14
VDD
C₂
R_DT1
T₁
Q₁
L_F
Q₄
C_F
C_SS
R_SC1
R_T
4 SS
5 SC
6 RT
7 VS
8 COMP
GATE 13
DT2 12
R_DT2
GND 11
CS 10
R_SC2
FB 9
Q₃
R_S
C₃
Q₂
C₄
Vo
+
R₃
R₄
-
C_Z
R_P
C_P
A122104
Supertex, Inc. • 1235 Bordeaux Drive, Sunnyvale, CA 94089 • Tel: [phone] • FAX: [phone] • www.supertex.com