US4742316A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pulse-width modulator
Assignee: Nokia of America Corp
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Filing: 1987-04-13
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Granted: 1988-05-03
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Expires: 2007-04-13
Abstract
Abstract A pulse-width modulator comprising a square-wave generator which triggers a monostable multivibrator driven by a controllable constant current source, the multivibrator having a capacitor as a timing element. The output of the multivibrator controls a gate circuit to which the square wave is also applied, thereby controlling the width of the square wave output from the gate circuit. The modulator can be assembled from standard CMOS building blocks and several external components, thereby achieving a power dissipation below 10 mW. If the current source is controlled by a CMOS variable-gain amplifier, the modulator can serve as the control circuit of a clocked direct voltage converter having internal losses below 25 mW.
Inventors
- 👤 Thomas Riedger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 06:05
CPC Classifications
H; H03; H03K; H03K7/00; H03K7/08
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
128 words
A pulse-width modulator for receiving from a square-wave generator (3) a periodic square-wave pulse signal (4a) having a fixed duty cycle and a fixed frequency, and for modulating such square-wave signal in accordance with an input signal (1a), said modulator comprising: a retriggerable monostable multivibrator (6); a timing circuit comprising a capacitor (7) and a current source (1) for charging said capacitor, said current source being controlled by the input signal; and an AND-gate (5); the square-wave pulse signal (4a) being applied to a trigger input (6a) of the multivibrator (6) and to an input (5a) of the AND-gate (5); said multivibrator (6) being triggered by falling edges of the square-wave signal, and producing an output signal which is applied to another input (5b) of said AND-gate (5).
Claim 2
Dependent Claim
128 words
A pulse-width modulator for receiving from a square-wave generator (3) a periodic square-wave pulse signal (4a) having a fixed duty cycle and a fixed frequency, and for modulating such square-wave signal in accordance with an input signal (1a), said modulator comprising: a retriggerable monostable multivibrator (6); a timing circuit comprising a capacitor (7) and a current source (1) for charging said capacitor, said current source being controlled by the input signal; and an AND-gate (5); the square-wave pulse signal (4a) being applied to a trigger input (6a) of the multivibrator (6) and to an input (5a) of the AND-gate (5); said multivibrator (6) being triggered by falling edges of the square-wave signal, and producing an output signal which is applied to another input (5b) of said AND-gate (5).
Claim 3
Dependent Claim
55 words
A pulse-width modulator as claimed in claim 1, characterized in that said current source (1) comprises a transistor and a resistor connected to the emitter of said transistor, the collector of said transistor being connected to a terminal of the capacitor (7) and the base of the transistor being triggered by the input signal (1a).
Claim 4
Dependent Claim
46 words
A pulse-width modulator as claimed in claim 1, characterized in that the input signal (1a) is supplied by a differential amplifier (2) having an input for receiving a controlling variable voltage and another input for receiving a reference voltage produced by a reference voltage source (3).
Claim 5
Dependent Claim
45 words
A pulse-width modulator as claimed in claim 3, characterized in that the differential amplifier (2), the reference voltage source (3), the square-wave generator (4), the gate circuit (5), the monostable multivibrator (6) and the controllable current source (1) are comprised in a monolithically integrated circuit.
Claim 6
Dependent Claim
32 words
A pulse-width modulator as claimed in claim 3, characterized in that the monostable multivibrator (6), the square-wave generator (4), the gate circuit (5) and the differential amplifier (2) are implemented in CMOS-technology.
References Cited (Backward Citations)
US3452297A
Cited
US3568094A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-05-03 | 1991-11-02 | 1992-05-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-03 | 1995-11-02 | 1996-05-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-03 | 1999-11-02 | 2000-05-03 | $7700.00 | Window Closed / Lapsed |