Patent EP0081891A1 successfully refreshed from Google Patents.
EP0081891A1
Expired / Lapsed
EP
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Fixed frequency voltage regulator
Assignee: Motorola Solutions Inc
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Filing: 1982-12-14
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Granted: —
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Expires: 2002-12-14
Abstract
Abstract A fixed frequency, variable duty cycle voltage regulator' having a precision reference voltage source (28) is provided. The reference voltage source (28) has a variable temperature coefficient. The output of the precision reference voltage source (28) is combined by a digitally switched attenuator to provide a staircase waveform to a comparator (44). This variable staircase waveform is compared against the output of an alternator (10). The comparator (44) sets the output of a flip-flop (48) to an off state when the staircase waveform goes below the output from the alternator (10). This removes the drive from a current switch (51, 52) which switches off the current flow through the field coil (19) of the alternator (10).
Inventors
- 👤 Mihaly Lamoth
- 👤 Heinz Lehning
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 19:43
CPC Classifications
H; H02; H02P; H02P9/00; H02P9/14; H02J; H02J7/00; H02J7/14; H02J7/16; H02J7/24; H02J7/2434; Y; Y02; Y02T; Y02T10/00; Y02T10/80; Y02T10/92
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
118 words
A fixed frequency voltage regulator useable in an automotive battery charging system, characterised by a temperature stable voltage reference (28) providing an output; an oscillator (29) providing an output; a digitally switched attenuator (32-35, 38-41) coupled to the output of the oscillator and providing an output which is combined with the output of the voltage reference; a comparator (44) having a first and a second input and providing an output, the first input receiving the combined output from the attenuator and the voltage reference; a first flip-flop (48) coupled to the output of the comparator and providing an output; and current switching means (51,52) coupled to the output of the first flip-flop for controlling the current switching means.
Claim 2
Dependent Claim
118 words
A fixed frequency voltage regulator useable in an automotive battery charging system, characterised by a temperature stable voltage reference (28) providing an output; an oscillator (29) providing an output; a digitally switched attenuator (32-35, 38-41) coupled to the output of the oscillator and providing an output which is combined with the output of the voltage reference; a comparator (44) having a first and a second input and providing an output, the first input receiving the combined output from the attenuator and the voltage reference; a first flip-flop (48) coupled to the output of the comparator and providing an output; and current switching means (51,52) coupled to the output of the first flip-flop for controlling the current switching means.
Claim 3
Dependent Claim
21 words
The fixed frequency regulator of claim 1 further characterised by a reference means coupled to the second input of the comparator.
Claim 4
Dependent Claim
83 words
The fixed frequency regulator of claim 1 further characterised by a logic gate (43) coupled to the digitally switched attenuator and providing a control signal to the flip-flop so that the fixed frequency voltage regulator is able to operate at an output voltage of the charging system which has high voltage steps superimposed by forcing the current switching means into a conducting state with a fixed repetition frequency and by switching the current switching means off by using the output of the comparator.
Claim 5
Dependent Claim
110 words
The fixed frequency regulator of claim 1 or 3 further characterised by current sensing means (76) coupled in series with the current switching means for sensing current in the current switching means; a second comparator (74) having a first input coupled to the current sensing means and providing an output; a second flip-flop (72) coupled to the output of the second comparator and providing an output; and a second logic gate (73) having a first input coupled to the output of the first flip-flop and having a second input coupled to the output of the second flip-flop, the second logic gate providing an output for controlling the current switching means.
Claim 6
Dependent Claim
30 words
The fixed frequency regulator of claim 4 further characterised by a differentiator (71) coupled between the output of the first logic gate and a second input of the second flip-flop.
Claim 7
Dependent Claim
25 words
The fixed frequency regulator of claim 1 further characterised in that the combined output of the attenuator and the voltage reference is a staircase signal.
Claim 8
Dependent Claim
27 words
The fixed frequency regulator of claim 6 further characterised in that the attenuator comprises dividers (38-41) coupled to the oscillator and resistors (32-35) coupled to the dividers.
Claim 9
Dependent Claim
42 words
The fixed frequency regulator of claim 1 further characterised in that the temperature stable voltage reference is a bandgap reference circuit including a plurality of diodes connected in series to provide an output reference voltage which is higher than the bandgap voltage.
References Cited (Backward Citations)
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