9

HV311

Application Circuit 3

Application Circuit 4

Note:

A capacitor may be needed to slow PWRGD dv/dt if gate oscillations are observed when V

Note:

A capacitor may be needed to slow PWRGD dv/dt if gate oscillations are observed when V

-48V

C

LOAD

+5V

8

3

2

COM

1

GND

Optocoupler

R4

12.5mW

R1

487kΩ

R2

6.81kΩ

R3

9.76kΩ

Q1

IRF530

C1

10nF

5

7

4

6

DC/DC

PWM

CONVERTER

ENABLE

R

LOAD

VDD

UV

OV

VEE

SENSE GATE

RAMP

HV311

PWRGD

-48V

C

LOAD

+5.0V

8

3

2

COM

1

GND

Optocoupler

R4

60mΩ

R1

487kΩ

R2

6.81kΩ

R3

9.76kΩ

Q1

IRF530

C1

10nF

5

7

4

6

DC/DC

PWM

CONVERTER

VDD

UV

OV

VEE

SENSE GATE

RAMP

HV311

PWRGD

ENABLE

In some applications the PWRGD signal is used to activate load circuitry on the isolated output side of the DC/DC PWM

Converter. In this situation an optocoupler is needed to provide the required isolation as shown below.

When the details of the load ENABLE circuitry is not known, using an optocoupler always provides a safe solution.