HA16108P View Datasheet(PDF) - Renesas Electronics

Part Name

Description

View to exact match

HA16108P

PWM Switching Regulator for High-performance Voltage Mode Control

Renesas Electronics 

HA16107P/FP, HA16108P/FP

Function and Timing Chart

Triangle Waveform and PWM Output

• Timing chart (during normal operation)

VTH 4.2 V typ

E/O

CT

2VBE

VTL 2.2 V typ

VRT2

0V

VIN

OUT

0V

Triangle waveform

is output to CT pin

• Oscillator equivalent circuit

×2

×2

×2

I1 I1

Dead band tON

tDB

9

RT2 VRT2

8

I2

6

7

RT1

CT

2I2

×2

0.6 V

Vref

(connected internally)

−

+

Comparator for

triangle waveform

oscillation

−

+

The ×2s are transistors whose emitter area is doubled.

I1

=

Vref − 2VBE

RT1

I2 =

Vref − 2VBE

RT2

tDB =

CT × RT1 × 2V

Vref − 2VBE

≈ 0.4 × CT × RT1 (s)

tON

≈

tDB

RT2

2RT1 − RT2

(s)

Du max = RT2

2RT1

fOSC

≈

1

− Du max

tDB

(Hz)

Note: When fOSC is high, the actual value will differ from that given by the formula due to the delay time.

Determine the correct constants after constructing a test circuit.

Rev.4.00 Jun 15, 2005 page 5 of 39

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