APW7068 Datasheet, PDF (1/26 Pages) Anpec Electronics Coropration – Synchronous Buck PWM and Linear Controller with 0.8V Reference Out Voltage

APW7068
Synchronous Buck PWM and Linear Controller with 0.8V Reference Out Voltage
Features
General Description
• Two Regulated Voltages and REF_OUT
- Synchronous Buck Converter
- Linear Regulator
- REF_OUT = 0.8V±1% with 3mA source current
• 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
• 300KHz Fixed Switching Frequency
• Voltage Mode PWM Control Design and Up to
89%(Typ.) Duty Cycle
• Under-Voltage Protection Monitoring Linear
Output
• Over-Voltage Protection Monitoring PWM Output
• Over-Current Protection for PWM Output
- Sense Low-side MOSFET’s R_DS(ON)
• SOP-14, QSOP-16 and QFN-16 packages
• Lead Free Available (RoHS Compliant)
Applications
• Graphic Cards
The APW7068 integrates synchronous buck
PWM, linear controller, and 0.8V Reference Out Voltage,
as well as the monitoring and protection functions
into a single package. The fixed 300KHz switching
frequency synchronous PWM controller drives
dual N-channel MOSFETs, which provides one controlled
power output with over-voltage and over-current
protections. Linear controller drives an external
N-channel MOSFET with under-voltage protection.
The APW7068 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 APW7068 with excellent protection functions:
POR, OCP, OVP 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 the voltage of OCSET pin. When the out-
put 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 voltage of FBL pin for short-circuit protection. When
the V_FBL is less than 50% of V_REF, the controller will
shutdown the IC directly. The Over-Voltage Protection
(OVP) monitors the voltage of FB. When the V_FB is
over 135% of V_REF, the controller will make Low-
side gate signal fully turn on until the fault events are
removed.
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.2 - Jun., 2006
www.anpec.com.tw