UC3842BN 查看數據表（PDF） - Motorola => Freescale

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产品描述 (功能)

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UC3842BN

HIGH PERFORMANCE CURRENT MODE CONTROLLERS

Motorola => Freescale 

UC3842B, 43B UC2842B, 43B

Figure 32. Slope Compensation

VCC

Vin

7(12)

MPS3904

8(14)

RT

R

Bias

R

5.0V Ref

+

–

36V

+

–

7(11)

From VO RSlope CT 4(7)

Ri

2(3)

Rd

Cf

Rf

Osc

+

–m

1.0mA 2R

S

Q

R

EA

R 1.0V Comp/Latch

6(10)

5(8)

1(1)

– 3.0m

m

3(5)

RS

5(9)

The buffered oscillator ramp can be resistively summed with either the voltage

feedback or current sense inputs to provide slope compensation.

Figure 33. 27 W Off–Line Flyback Regulator

4.7Ω

MDA

202

115 Vac

+ 250

56k

7(12)

0.01

8(14)

10k

4700pF 4(7)

18k

2(3)

100

4.7k pF

150k

1(1)

R

Bias

R

Osc

+

EA

5.0V Ref

+

–

+

–

S

Q

R

Comp/Latch

5(9)

Test

Conditions

Results

Line Regulation: 5.0 V Vin = 95 to 130 Vac

±12 V

∆ = 50 mV or ± 0.5%

∆ = 24 mV or ± 0.1%

Load Regulation: 5.0 V

±12 V

Vin = 115 Vac,

Iout = 1.0 A to 4.0 A

Vin = 115 Vac,

Iout = 100 mA to 300 mA

∆ = 300 mV or ± 3.0%

∆ = 60 mV or ± 0.25%

Output Ripple: 5.0 V Vin = 115 Vac

±12 V

40 mVpp

80 mVpp

Efficiency

Vin = 115 Vac

All outputs are at nominal load currents, unless otherwise noted

70%

4.7k

T1

3300

pF

1N4935

+ 68

100

1N4935

+

47

MBR1635

L1

5.0V/4.0A

+

+

2200

1000

5.0V RTN

MUR110

12V/0.3A

+ L2 +

1000

10

±12V RTN

1N4937

7(11)

22

1000 +

MUR110

680pF

10 +

L3

–12V/0.3A

2.7k

1N4937

6(10)

1N5819

MTP

4N50

5(8)

1.0k

3(5)

0.5

470pF

L1 – 15 µH at 5.0 A, Coilcraft Z7156

L2, L3 – 25 µH at 5.0 A, Coilcraft Z7157

T1 – Primary: 45 Turns #26 AWG

Secondary ±12 V: 9 Turns #30 AWG (2 Strands) Bifiliar

Wound

Secondary 5.0 V: 4 Turns (six strands) #26 Hexfiliar Wound

Secondary Feedback: 10 Turns #30 AWG (2 strands)

Bifiliar Wound

Core: Ferroxcube EC35–3C8

Bobbin: Ferroxcube EC35PCB1

Gap: ≈ 0.10” for a primary inductance of 1.0 mH

14

MOTOROLA ANALOG IC DEVICE DATA

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