Integrated pulse-width modulation circuit with thermal shutdown circuit
First Claim
Patent Images
1. An integrated pulse-width modulation circuit comprising:
- a pulse-width modulation circuit having a PWM output at which a PWM signal is produced, and a masking output at which a masking signal is produced, said pulse-width modulation circuit also including a PWM disable input, wherein said masking signal is produced a predetermined time period prior to a transition of said PWM signal, and wherein said PWM signal is disabled in response to signals supplied to said PWM disable input;
a power output device connected to said PWM output and responsive to said PWM signal to produce a switching power signal in accordance with said PWM signal;
a thermal shutdown circuit including a TSD output connected to said PWM disable input, said thermal shutdown circuit responding to the temperature of the integrated pulse-width modulation circuit, said thermal shutdown circuit producing a TSD signal at said TSD output when the temperature of the integrated pulse-width modulation circuit exceeds a predetermined temperature, said thermal shutdown circuit also including a TSD disable input wherein said TSD output is disabled and said TSD signal is disabled in response to signals supplied to said TSD disable input; and
a TSD masking circuit, said TSD masking circuit supplying a predetermined duration TSD disable signal to said TSD disable input in accordance with said masking signal.
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Abstract
An integrated pulse-width modulation circuit with conditional temperature protection circuitry includes logic circuitry, a power output device, thermal shutdown circuitry to disable the power output device when the die temperature exceeds a predetermined limit, and a masking circuit that disables the thermal shutdown circuit during short term thermal increases such as those that occur when an inductive load turn off event takes place.
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Citations
12 Claims
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1. An integrated pulse-width modulation circuit comprising:
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a pulse-width modulation circuit having a PWM output at which a PWM signal is produced, and a masking output at which a masking signal is produced, said pulse-width modulation circuit also including a PWM disable input, wherein said masking signal is produced a predetermined time period prior to a transition of said PWM signal, and wherein said PWM signal is disabled in response to signals supplied to said PWM disable input; a power output device connected to said PWM output and responsive to said PWM signal to produce a switching power signal in accordance with said PWM signal; a thermal shutdown circuit including a TSD output connected to said PWM disable input, said thermal shutdown circuit responding to the temperature of the integrated pulse-width modulation circuit, said thermal shutdown circuit producing a TSD signal at said TSD output when the temperature of the integrated pulse-width modulation circuit exceeds a predetermined temperature, said thermal shutdown circuit also including a TSD disable input wherein said TSD output is disabled and said TSD signal is disabled in response to signals supplied to said TSD disable input; and a TSD masking circuit, said TSD masking circuit supplying a predetermined duration TSD disable signal to said TSD disable input in accordance with said masking signal. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An integrated pulse-width modulation circuit comprising:
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PWM circuit means for producing a PWM signal, said PWM circuit means having a PWM output at which a PWM signal is produced, and a masking output at which a masking signal is produced, said PWM circuit means also including a disable input, wherein said masking signal is produced a predetermined time period prior to a high to low transition of said PWM signal, and wherein said PWM signal is disabled in response to signals supplied to said PWM disable input; a power output device connected to said PWM output and responsive to said PWM signal to produce a switching power signal in accordance with said PWM signal; thermal shutdown circuit means for producing a thermal shutdown signal, said thermal shutdown circuit including a TSD output connected to said PWM disable input, said thermal shutdown circuit means responding to the temperature of the integrated pulse-width modulation circuit, said thermal shutdown circuit means producing a TSD signal at said TSD output when the temperature of the power output device exceeds a predetermined temperature, said thermal shutdown circuit means also including a TSD disable input wherein said TSD output is disabled and said TSD signal is disabled in response to signals supplied to said TSD disable input; and a TSD masking circuit, said TSD masking circuit supplying a predetermined duration TSD disable signal to said TSD disable input in accordance with said masking signal. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification