LM193J/883 National Semiconductor, LM193J/883 Datasheet - Page 4

• Manufacturer Part Number: LM193J/883
• Description: IC,VOLT COMPARATOR,DUAL,BIPOLAR,DIP,8PIN,CERAMIC
• Manufacturer: National Semiconductor

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Applications
*
Figure 5 shows a 6 amp, variable output switching regulator
for general purpose applications. An LM105 positive regula-
tor is used as the amplifier-reference for the switching regu-
lator. Positive feedback to induce switching is obtained from
the LM105 at pin 1 through an LM103 diode. The positive
feedback is applied to the internal amplifier at pin 5 and is
independent of supply voltage. This forces the LM105 to
* Sixty turns wound on arnold type A-083081-2 core.
†
*
Solid tantalum.
Four devices in parallel.
(Continued)
FIGURE 4. Detailed Structure of one Section of the Power Transistor
FIGURE 5. 6 Amp Variable Output Switching Regulator
4
drive the pass devices either “on” or “off,” rather than linearly
controlling their conduction. Negative feedback, delayed by
L1 and the output capacitor, C2, causes the regulator to
switch with the duty cycle automatically adjusting to provide
a constant output. Four LM195’s are used in parallel to
obtain a 6 amp output since each device can only supply
about 2 amps. Note that no ballasting resistors are needed
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