SR036 Supertex Inc, SR036 Datasheet - Page 4

• Manufacturer Part Number: SR036
• Description: Inductorless / Dual Output Off-Line Regulators
• Manufacturer: Supertex Inc

SR036/SR037
Applications Information
Functional Block Diagram
Operating Principle
HV
Gate
Source
IN
The SR03x operates by controlling the conduction angle of the
external MOSFET as shown in Figure 1. When the rectified AC
V
CM
voltage is below the V
threshold, the pass transistor is turned
REF
TH
on. The pass transistor is turned off when the rectified AC is
Reg
V
above HV
. Output voltage (Vunreg) decays during the periods
OUT
IN(off)
when the switch is off and when the rectified AC is below the
output voltage. The amount of decay is determined by the load
and the value of C1. Since the switch only conducts with low
GND
voltages across it, power dissipation is minimized.
Switch ON
HV
IN
V
TH
V
UNREG
V
REG
not to scale
Figure 1: Typical Waveforms
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