HV9606
Initial Release
HV9606 Current-Mode PWM Controller with Supervisor
Features
Synchronous Forward, Forward, and Flyback Controller
Lowest External Parts Count, Smallest Magnetics
Eliminates Bootstrap Transformer Winding
Supervisor Circuit Reduces Output Capacitance* up to 40%
Supervisor Circuit Functions as
碌P
Supply Monitor and POR
15V to 250V Start-Up Regulator with START/STOP Control
<1mA Operating, <6碌A(chǔ) Standby Input Current
V
DD
Powered Operation down to 2.9V
Charge Pump Gate Drive Supply
Programmable Soft Start
Under Voltage Lockout with Programmable Hysteresis
<50% Duty Cycle Operation
15kHz to 400kHz Fixed Frequency PWM Operation
Fault Tolerant Peer-to-Peer Synchronization
Precision
!1%
Band Gap Voltage Reference
Current Sense Leading Edge Blanking
Small SSOP-20 Footprint
*For short duration line loss, supervisor disables soft start if output
within tolerance when V
IN
returns and thus reduces holdup
requirements.
General Description
The HV9606 PWM controller allows the design of high efficiency
(>90%) power supplies for distributed board mounted power (BMP)
applications. Due to its high frequency capability it can provide
high currents (20A @ 3.3V) with small transformers and due to its
low internal operating voltage and current is also able to achieve
high efficiencies in low power applications.
The HV9606 utilizes fixed frequency current mode control with duty
cycle internally limited to <50%. It supports both isolated and non-
isolated topologies and provides all the necessary functions to
implement a flyback, forward or synchronous forward converter
with a minimum of external parts. Due to its low V
DD
operation the
bootstrap magnetic winding is eliminated in non-isolated
topologies. An on chip charge pump generates the gate drive
voltage for driving an external N-channel MOSFET and eliminates
the need for clamping by offering 250V immunity to high voltage
transients common in telecom and network systems. It conforms
to the requirements of IEEE 802.3 Powered Ethernet and ETR-080
ISDN specifications.
The oscillator is programmable and provides fault tolerant peer-to-
peer synchronization to other similar circuits or master clock. The
chip draws almost no current (<6碌A(chǔ) @ V
IN
< 20V) until the
programmable START/STOP thresholds of the start-up regulator
are satisfied. It can also be powered via the V
DD
pin, rather than
the V
IN
pin, in the range of 2.9V to 5.5V.
Other functions include leading edge current sense blanking,
programmable SOFT START, precision
!1%
band gap reference
and a SUPERVISOR CIRCUIT. The SUPERVISOR can provide
housekeeping functions such as
碌P
supply monitoring and reset,
soft start inhibit for rapid restart on short duration input voltage
interruption. It also minimizes input and output capacitance
requirements.
Applications
Powered Ethernet and VoIP Terminals
Cable Modems and Amplifiers
ISDN Network Terminations, Terminals and Adapters
Network Equipment
Servers, PCs and Peripheral Equipment
Telecommunication Systems and Terminals
Distributed Board Mounted Power
Battery Backup Systems
Portable Power Applications
Automotive and Heavy Equipment
Typical Application Circuit
10W Non-Isolated 48V to 3.3V Flyback Converter
R3
R2
C2
C9
1
VDD
STATUS
20
Q1
2
START
SENSE
19
To uP
RESET
Pin.
R1
3
STOP
FB
18
C4
5
REF
HV9606
+48V
C7
4
Vin
COMP
C8
R6
T1
D1
R7
C10
17
NI
16
+3.3V
6
SS
CA
15
C3
7
SYNC
C6
CB
14
C1
R4
8
RT
VX2
13
C5
9
SGND
GATE
M1
R8
R10
12
10
PGND
CS
11
R9
R5
GND
To SYNC pin of other HV9606 PWMs.
GND
1
4/15/2002-R.L2
Supertex, Inc. 1235 Bordeaux Drive, Sunnyvale, CA 94089 TEL: (408) 744-0100 FAX: (408) 222-4895 www.supertex.com
SUPERTEX
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