PQ1PF1 查看數據表（PDF） - Sharp Electronics

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PQ1PF1

Primary Regulator for Switching Power Supply (50W Class)

Sharp Electronics 

Primary Regulators

s Precautions in Designing

1 Starting circuit

Fig.7 Diagram of Starting Circuit and It's Peripheral Portion

V IN

DC

R9

5

2

1

VCC

GND

VDS

PQ1PF1

D6

+

C10

Auxiliary winding

PQ1PF1

1-1 Setting starting resistance

Concerning stand-by current (0.15mA) MAX. and *starting time of power supply, the value of starting resistor R9 is obtained

by the following equation.

*For ex.) during 0.5s, C10 is charged to the level of operation starting voltage (18.5V) MAX.

R9= (VIN(DC)- VCC(ON)) / [0.15X10-3+(18.5XC10)/0.5]

VIN(DC) : DC input voltage

(Minimum input voltage which is necessary for IC to start operation ex. 70VACX√ 2=99VDC)

VCC(ON) : Operation starting voltage of IC (18.5V MAX.)

When IC start to operate, current to VCC terminal increases. The current is supplied by an auxiliary winding of main tramsformer.

After rectification of auxiliary winding, voltage (both side of C10) must be set on operation stopping voltage (VCC(OFF)=9.3V

Typ.) or more. MOS-FET driving voltage in IC is about 13V, which is applied from Vcc terminal. When Vcc is about 16.5V

or more, MOS-FET driving voltage is in optimum condition due to built-in voltage regulator circuit for driving voltage.

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