Transient protected isolator output stage
First Claim
1. In a plural output voltage regulator operating from a single d-c source, wherein a single circuit provides plural regulated output voltages, and currents, which operate individually and independently from each other so as to withstand output malfunctions created by adverse load conditions such as shorting to ground or below or to a high voltage line, a plurality of transient protected isolator output stage (TPIOS) circuits, each one comprising:
- an input for supplying a reference voltage to said TPIOS circuit;
an NPN output pass transistor, having emitter, base and collector electrodes, which provides one of said output voltages at its emitter;
a primary negative feedback loop which compares said output voltage with said reference voltage and drives the base of said output pass transistor whereby said output voltage is regulated; and
a secondary negative feedback loop which compares a fraction of said output current with a reference current and controls the base of said output pass transistor to limit said output current to a predetermined maximum value.
1 Assignment
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Accused Products
Abstract
An automotive voltage regulator is disclosed to have plural regulated outputs using a transient protected isolator output stage (TPIOS) that prevents a system fault condition on any one output from adversely affecting the other outputs. In an automotive environment employing a nominal 14-volt supply, an individual output can be taken from -4 to +26 volts without causing damage or having any significant reaction on the non-faulted outputs. The circuit employs a relatively small NPN output pass transistor and, therefore, requires a relatively low value stabilizing bypass capacitor.
6 Citations
9 Claims
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1. In a plural output voltage regulator operating from a single d-c source, wherein a single circuit provides plural regulated output voltages, and currents, which operate individually and independently from each other so as to withstand output malfunctions created by adverse load conditions such as shorting to ground or below or to a high voltage line, a plurality of transient protected isolator output stage (TPIOS) circuits, each one comprising:
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an input for supplying a reference voltage to said TPIOS circuit; an NPN output pass transistor, having emitter, base and collector electrodes, which provides one of said output voltages at its emitter; a primary negative feedback loop which compares said output voltage with said reference voltage and drives the base of said output pass transistor whereby said output voltage is regulated; and a secondary negative feedback loop which compares a fraction of said output current with a reference current and controls the base of said output pass transistor to limit said output current to a predetermined maximum value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification