SHUNT REGULATOR
A unique feature of the ML2283 is the inclusion of a shunt
regulator connected from V+ terminal to ground which
also connects to the VCC terminal (which is the actual
converter supply) through a silicon diode as shown in
Figure 8. When the regulator is turned on, the V+ voltage
is clamped at 11VBE set by the internal resistor ratio. The
typical I-V of the shunt regulator is shown in Figure 9.
ML2280, ML2283
It should be noted that before V+ voltage is high enough
to turn on the shunt regulator (which occurs at about
5.5V), 35kW resistance is observed between V+ and GND.
When the shunt regulator is not used, V+ pin should be
either left floating or tied to GND. The temperature
coefficient of the regulator is –22mV/°C.
12V
V+
VCC
I+→
CURRENT LIMITING
RESISTOR, I+ ≤15mA
28.8kΩ
3.2kΩ
GND
3.2kΩ
Figure 9. Shunt Regulator
I+
15mA
SLOPE =351kΩ
V+
5.5V 6.9V
Figure 10. I-V Characteristic of the Shunt Regulator
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