APW7068(2009) 查看數據表（PDF） - Anpec Electronics

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APW7068
(Rev.:2009)

Synchronous Buck PWM and Linear Controller with 0.8V Reference Out Voltage

Anpec Electronics 

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 Out-

put

• Over-Voltage Protection Monitoring PWM Output

• Over-Current Protection for PWM Output

- Sense Low-side MOSFET’s RDS(ON)

• SOP-14, SSOP-16 and Compact QFN4x4-16 pack-

ages

• Lead Free and Green Devices Available

(RoHS Compliant)

Applications

• Graphic Cards

Simplified Application Circuit

12V

VIN2

Q3

VOUT2

Linear PWM

Controller Controller

VIN1

Q1

L VOUT1

Q2

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 synchro-

nous 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-volt-

age protection.

The APW7068 provides excellent regulation for output load

variation. An internal 0.8V temperature-compensated ref-

erence 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 V supply voltage exceeds its threshold

CC12

voltage while the controller is running, and a built-in digi-

tal 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 , comparing with the voltage of OCSET

DS(ON)

pin, V The maximum V voltage is limited to the

OCSET.

OCSET

internal default value 0.25V. In addition, when OCSET pin

is floating (no ROCSET resistor), the over current threshold

will also be internal default value, 0.25V. When the output

current reaches the trip point, the controller will shutdown

the IC directly, and latch the converter’s output. The Un-

der-Voltage Protection (UVP) monitors the voltage of FBL

pin for short-circuit protection. When the VFBL is less than

50% of VREF, the controller will shutdown the IC directly.

The Over-Voltage Protection (OVP) monitors the voltage

of FB. When the VFB is over 135% of VREF, 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.6 - Aug., 2009

www.anpec.com.tw

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