APW7067N_08 Datasheet, PDF (1/24 Pages) Anpec Electronics Coropration – Synchronous Buck PWM and Linear Controller

APW7067N
Synchronous Buck PWM and Linear Controller
Features
• Provided Two Regulated Voltages
- Synchronous Buck Converter
- Linear Regulator
• Single 12V Power Supply Required
• Excellent Both Output Voltage Regulation
- 0.8V Internal Reference
- ±1% Over Line Voltage and Temperature
• Integrated Soft-Start for PWM and Linear Outputs
• Programmable Frequency Range from 150kHz
to 1000kHz
• Voltage Mode PWM Control Design and Up to 89%
(Typ.) Duty Cycle
• Under-Voltage Protection for PWM and Linear
Output
• Over-Current Protection for PWM Output
- Sense Low-Side MOSFET’s R_DS(ON)
• SOP-14, QSOP-16 and QFN4x4-16 packages
• Lead Free and Green Devices Available
(RoHS Compliant)
Typical Application Circuit
General Description
The APW7067N integrates synchronous buck PWM and
linear controller, as well as monitoring and protection
functions into a single package. The synchronous PWM
controller drives dual N-channel MOSFETs, which provides
one controlled power output with under-voltage and over-
current protections. Linear controller drives an external
N-channel MOSFET with under-voltage protection.
The APW7067N provides excellent regulation for output
load variation. An internal 0.8V temperature-compensated
reference voltage is designed to meet the requirement
of low output voltage applications. The switching frequency
is adjustable from 150kHz to 1000kHz.
The APW7067N with excellent protection functions: POR,
OCP and UVP. The Power-On-Reset (POR) circuit can
monitor VCC12 supply voltage exceeds its threshold
voltage while the controller is running, and a built-in
digital soft-start provides both outputs with controlled
rising voltage. The Over-Current Protection (OCP)
monitors the output current by using the voltage drop
across the lower MOSFET’s R_DS(ON), comparing with
internal V_OCP (0.25V), eliminating the need for a current
sensing resister. When the output current reaches the
trip point, the controller will shutdown the IC directly, and
latch the converter’s output. The Under-Voltage Protection
(UVP) monitors the voltages of FB and FBL pins for short-
circuit protection. When the V or V is less than 50%
FB
FBL
of V_REF, the controller will shutdown the IC directly.
12V
V_IN2
Q3
V_OUT2
Linear ^PWM
Controller ^Controller
R_{FS_DIS}
V_IN1
Q1
L ^VOUT1
Applications
• Graphic Cards
Q2
ANPEC reserves the right to make changes to improve reliability or manufacturability 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.3 - Mar., 2008
www.anpec.com.tw