APW7158 Datasheet, PDF (1/24 Pages) Anpec Electronics Coropration – Dual Synchronous Buck PWM Controllers

APW7158
Dual Synchronous Buck PWM Controllers
Features
General Description
• Two Synchronous Buck Converters(OUT1,OUT2)
• Converter Input Voltage Range up to 12V
• 0.6V Reference for OUT1 with 0.8% Accuracy
• 3.3V Reference for OUT2 with 0.8% Accuracy
• Both Outputs have Independent Soft-Start and
Enable Functions
• Internal 300kHz Oscillator and Programmable
Frequency Range from 70 kHz to 800kHz
• 180 Degrees Phase Shift etween OUT1 and OUT2
• Short-Circuit Protection
• Thermally Enhanced SOP-20 Package
• Lead Free and Green Devices Available
(RoHS Compliant)
Applications
• Graphic Cards
• Low-Voltage Distributed Power Supplies
• SMPS Application
Simplified Application Circuit
The APW7158 has two synchronous buck PWM control-
lers with high precision internal references voltage to of-
fer accurate outputs. The PWM controllers are designed
to drive two N-channel MOSFETs in synchronous buck
topology. The device requires 12V and 5V power supplies.
If the 5V supply is not available, the device can offer an
optional shunt regulator 5.8V for 5V supply.
Both outputs have independent soft-start and enable func-
tions combined on the SS/EN pin. Connecting a capaci-
tor from each SS/EN pin to the ground for setting the soft-
start time, and pulling the SS/EN pin voltage below 1V to
disable regulator. The device also offers 180°phase shift
function between OUT1 and OUT2.
The default switching frequency is 300kHz (keep the FS
pin open or short to GND), and the device also provides
the programmable switching frequency function to ad-
just the switching frequency from 70kHz to 800kHz. Con-
necting a resistor from FS pin to GND increases the
switching frequency. Conversely, connecting a resistor
from FS pin to VCC12 decreases the switching frequency.
There is no current sensing or under-voltage sensing on
the APW7158. However, it provides a simple short-circuit
protection by monitoring the COMP1 pin and COMP2 pin
for over-voltage. When any of two pins exceed their trip
point and the condition keeps for 1-2 internal clock cycles
(3-6us at 300kHz), all regulators are latched off.
APW7158
Pin Configuration
FB1 1
COMP1 2
COMP2 3
FB2 4
REFIN 5
REFOUT 6
SS1/EN1 7
SS2/EN2 8
VREF 9
FS10
20 VCC
19 BOOT1
18 UGATE1
17 VCC12
16 LGATE1
15 LGATE2
14 PGND
13 BOOT2
12 UGATE2
11 GND
ANPEC reserves the right to make changes to improve reliability or manufacturSability without notice, and
advise customers to obtain the latest version of relevant information to verify before placing orders.
Copyright © ANPEC Electronics Corp.
1
Rev. A.2 - Aug., 2009
www.anpec.com.tw