MP6001 – MONOLITHIC FLYBACK/FORWARD DC-DC CONVERTER

INITIAL RELEASE – SPECIFICATIONS SUBJECT TO CHANGE

MP6001 Rev. 0.91

www.MonolithicPower.com

6

4/5/2006

MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.

© 2006 MPS. All Rights Reserved.

TM

High Voltage Startup

The MP6001 features a 100V startup circuit,

see Figure 1. When power is applied, the

capacitor at the VCC pin is charged through the

VIN pin. When the voltage at the VCC pin

crosses 6.0V without fault, the controller is

enabled. The VCC pin is then disconnected

4.5V, the VCC pin is reconnected to the VIN pin

VCC pin repeats this ramp cycle between 4.5V

and 6.0V. The VCC pin can be powered with a

voltage higher than 4.5V from an auxiliary

winding to reduce the power dissipated in the

internal startup circuit. The VCC pin is internally

clamped at 8V.

Under-Voltage and Over-Voltage Detection

The MP6001 includes a line monitor circuit.

Two external resistors form a voltage divider

from the input voltage to GND; its tap connects

to the LINE pin. The controller is operational

when the voltage at the UV/OV pin is between

1.2V and 3V. When the voltage at the UV/OV

pin goes out of this operating range, the

controller is disabled and goes into standby

mode. The LINE pin can also be used as a

remote enable. Grounding the UV/OV pin will

disable the controller.

Error Amplifier

The MP6001 includes an error amplifier with its

non-inverting input connected to internal 1.2V

reference voltage. The regulated voltage is fed

back through a resistor network or an

optocoupler to the FB pin. Figure 2 shows some

common error amplifier configurations.

--

+

1.2V

FB

C2

C3

R3

COMP

VCC

C1

PRIMARY

WINDING

R1

R2

D1

EA

34

6

--

+

1.2V

FB

COMP

VCC

MP6001_F02

C2

R2

R3

(a) Using Primary winding to provide feedback

(b) Feedback is from Secondary (Common Collector)

(c) Feedback is from Secondary (Common Emitter)

EA

34

6

--

+

1.2V

FB

COMP

VCC

EA

34

6

C2

Figure 2—Error Amplifier Configurations