MP6003 – MONOLITHIC FLYBACK/SEPIC DC-DC CONVERTER

MP6003 Rev. 1.01

www.MonolithicPower.com

14

1/26/2014

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Control Design

Generally, some of power supplies require the

galvanic isolation between a relatively high

input voltage and low output voltages. The most

widely used devices to transfer signals across

the isolation boundary are pulse transformers

and optocouplers.

--

+

--

+

S

Tr

D

d

R6

R3

Rb

R4

R1

R2

R5

C1

TL431

--

+

Figure 7—Simplified Circuit of Isolated

Power Supply with Optocoupler Feedback

The MP6003 uses current mode control to

achieve easy compensation and fast transient

response. A type II compensation network

which has two poles and one zero is needed to

stabilize

the

system.

The

practical

compensation parameters are provided in the

EVQ6003DN datasheet.

Boost Controller Application Design

Example 2

The MP6003 can be used as a boost controller

as shown in Figure 8.

MP6003

GND

COMP

FB

LINE

8

5

6

7

1

4

3

2

SW

RT

VCC

VIN

R6

63.4k

Ω

R2

200k

Ω

C4

10

μ F

16V

C2

1

μ F

200V

C3

10nF

L1

22

μ F/2.5A

D1

200V/1A

180V

20mA

R5

1.5k

Ω

R4

10k

Ω

R1

60.4

Ω

R3

10k

Ω

C1

10

μ F

25V

Figure 8—High Voltage LED Boost

Controller Circuit

Design Example

This design example shows an flyback topology

for industrial application. It has wide input

voltage rang from 36V to 80V and 5V output.

1

2

3

4

3

1

2

Figure 9—Reference Design Circuit for Flyback Application