US4933614A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Motor drive control circuit
Assignee: Alps Alpine Co Ltd
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Filing: 1989-01-11
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Granted: 1990-06-12
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Expires: 2009-01-11
Abstract
Abstract A blower motor drive control circuit is configured to maintain a fixed value of motor driving current to maintain a constant amount of air supply from an air conditioner regardless of changes in the amount of intake air.
Inventors
- 👤 Toshihiko Kawata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 21:57
CPC Classifications
B; B60; B60H; B60H1/00; B60H1/00642; B60H1/00814; B60H1/00821; B60H1/00828; F; F04; F04D; F04D27/00; F24; F24F; F24F11/00; F24F11/0001; G; G05; G05D; G05D7/00; G05D7/06; G05D7/0617; G05D7/0629; G05D7/0676; H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/285; H02P7/288; Y; Y10; Y10S; Y10S388/00; Y10S388/923; Y10S388/929; Y10S388/93
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
280 words
A motor drive circuit for a DC motor on which the mechanical load is varied and which is powered by a supply supplying an electric current to the DC motor, comprising: a drive transistor for controlling the electric current supplied from the power supply to the DC motor; a current sensing resistor for detecting the electric current supplied to the DC motor and providing an analog voltage, current value signal indicative thereof; amplifier means connected to both ends of said current sensing resistor for amplifying the current value signal of said current sensing resistor and providing an amplified current value signal, said amplifier means having a characteristic of producing an offset voltage signal below an offset level of said amplifier means due to an inter-terminal potential difference of said amplifier means; comparison means responsive to the current value signal obtained from said amplifier means for comparing the current value signal to a reference current value signal and providing a desired current value signal to said drive transistor for controlling the electric current supplied to the DC motor so as to compensate for mechanical load variations; setting means for providing a reference current value signal to said comparison means; and a voltage divider connected between said amplifier means and said comparison means for dividing the amplified current value signal of said amplifier means and providing a divided current value signal as an output to said comparison means which is a predetermined fractional amount of the amplified current value signal, wherein the range of the current value signal detected by said current sensing resistor which is affected by the offset voltage level of said amplifier means is decreased by said fractional amount.
Claim 2
Dependent Claim
280 words
A motor drive circuit for a DC motor on which the mechanical load is varied and which is powered by a supply supplying an electric current to the DC motor, comprising: a drive transistor for controlling the electric current supplied from the power supply to the DC motor; a current sensing resistor for detecting the electric current supplied to the DC motor and providing an analog voltage, current value signal indicative thereof; amplifier means connected to both ends of said current sensing resistor for amplifying the current value signal of said current sensing resistor and providing an amplified current value signal, said amplifier means having a characteristic of producing an offset voltage signal below an offset level of said amplifier means due to an inter-terminal potential difference of said amplifier means; comparison means responsive to the current value signal obtained from said amplifier means for comparing the current value signal to a reference current value signal and providing a desired current value signal to said drive transistor for controlling the electric current supplied to the DC motor so as to compensate for mechanical load variations; setting means for providing a reference current value signal to said comparison means; and a voltage divider connected between said amplifier means and said comparison means for dividing the amplified current value signal of said amplifier means and providing a divided current value signal as an output to said comparison means which is a predetermined fractional amount of the amplified current value signal, wherein the range of the current value signal detected by said current sensing resistor which is affected by the offset voltage level of said amplifier means is decreased by said fractional amount.
Claim 3
Dependent Claim
20 words
The motor drive circuit of claim 1 further comprising an integrator connected between said comparison means and said drive transistor.
References Cited (Backward Citations)
US4044287A
Cited
US4415790A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-06-11 | 1993-12-11 | 1994-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-11 | 1997-12-11 | 1998-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-11 | 2001-12-11 | 2002-06-12 | $7700.00 | Window Closed / Lapsed |