5

SR036/SR037

Applications Information, continued

220

µF

1

µF

SR036

or SR037

VN2460N8

HV

IN

GND

Gate

Source

V

OUT

(

Fuse

120VAC

or

240VAC

Figure 2: Example Circuit with Enable Control

1K

Ω

TN2106K1

ON/OFF

Figure 3: Generating Two Regulated Voltages

220

µF

1

µF

SR036

VN2460N8

1

µF

1M

Ω

Vz

5.6V

10K

Ω

120VAC

or

240VAC

Fuse

2N3904

HV

IN

GND

Gate

Source

V

OUT

Figure 2 is an example circuit using the SR036 or SR037 along

with a Supertex VN2460N8 MOSFET to generate an unregu-

lated voltage of approximately 18V and a regulated voltage of

3.3V for the SR036 or 5.0V for the SR037. The combined total

output current is typically 40mA. The TN2106K1 in series with a

1KΩ resistor can be added for applications requiring an enable

control.

For applications requiring two regulated voltages, an inexpen-

sive discrete linear regulator can be added to regulate the

unregulated output as show in Figure 3. The discrete linear

regulator consists of a Zener diode, a resistor and a bipolar

transistor. The regulated voltage, Vout1, is determined by the

Zener diode voltage minus the base-to-emitter voltage drop of

0.6V. Figure 3 uses a 5.6V Zener diode to obtain a 5.0V output.

Different Zener diode voltages can be used to obtain different

regulated output voltages.