MC34065–H, L MC33065–H, L

11

MOTOROLA ANALOG IC DEVICE DATA

Figure 25. Bipolar Transistor Drive

Figure 26. Isolated MOSFET Drive

Figure 27. Dual Charge Pump Converter

The totem–pole outputs can furnish negative base current for enhanced

transistor turn–off, with the addition of capacitor C1.

IB

+

–

0

Base Charge

Removal

Vin

C1

RS

–

+

Q1

+

_

+

–

–

+

+

–

5.0Vref

S

R

Q

VCC

Vin

16

PWM

Latch 1

7

6

D1

NP

NS

C

R

Isolation

Boundary

I

pk +

V

(Pin 6) *

1.4

3R

S

N

P

N

S

The capacitor’s equivalent series resistance must limit the Drive Output current to 400 mA. An additional series resistor may be required

when using tantalum or other low ESR capacitors. The positive output can provide excellent line and load regulation by connecting the

R2/R1 resistor divider as shown.

Output Load Regulation

IO (mA) +VO (V) –VO (V)

0

1.0

5.0

10

50

28.43

27.72

27.04

26.20

20.52

–13.89

–12.90

–12.25

–11.44

–5.80

–

+

+

_

+

_

–

+

+

–

–

+

+

–

–

+

+

+

+

+

15

1

3

2

4

5

14

13

12

1.0nF

12k

2.5V

R

R

Bias

Osc.

5.0Vref

20k

1.0mA

1.0mA

R

2R

1.0V

EA2

89

S

R

R

Q

PWM

Latch 2

S

Q

R

PWM

Latch 1

R

16

VCC = 15V

+

47

27

10

7

47

6

10

11

47

R2

R1

+VO ≈ 2.0 VCC

–VO ≈ –VCC

1N5819

1N5819

2R

250

µA

10

10

10

10

27

10

Connect to Pin 4 for

closed–loop regulation.

) V

O +

2.5

R

2

R

1

) 1

EA1

1.0V