Control circuit for vibrating compressors for protecting against excessive voltage and temperature
First Claim
1. A control circuit for vibrating compressors for converting d-c voltage into ac voltage to supply a-c voltage to a vibrating compressor comprisinga MOS-FET transistor for driving said vibrating compressor, a timer IC for generating pulses to switch said MOS-FET transistor, a timer forced-operation circuit for forcibly reversing the output of said timer IC at a timing at which a counter-electromotive voltage generated by said vibrating compressor during the OFF period of said MOS-FET transistor is restored in the vicinity of 0 volts, a driver for driving said MOS-FET transistor based on the output, of said timer IC, said driver including a capacitor for cutting d-c components in a gate of said MOSFET transistor so that said MOS-FET transistor is protected from damage due to malfunction of said control circuit, and a pulse width changing circuit for detecting an input voltage input into said vibrating compressor and lowering said input voltage to said vibrating compressor by changing the pulse width of output pulses of said timer IC when said input voltage is higher than a predetermined voltage which would cause damage to a valve of the vibrating compresor due to an overrun of a piston of the vibrating compressor.
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Accused Products
Abstract
A control circuit for vibrating compressors for converting d-c voltage into a-c voltage to supply a-c voltage to a vibrating compressor (1) comprising a MOS-FET transistor (2) for driving the vibrating compressor (1), a timer IC for generating pulses to switch the MOS-FET transistor (2), a timer forced operation circuit for forcibly reversing the output of the timer IC at a timing at which a counter-electromotive voltage generated by the vibrating compressor (1) during the OFF period of the MOS-FET transistor (2) is restored in the vicinity of 0 volts, a driver for driving the MOS-FET transistor (2) based on the output of the timer IC, and a pulse width changing circuit (9) for detecting an input voltage input into the vibrating compressor (1) and lowering the input voltage to the vibrating compressor (1) by changing the pulse width of output pulses of the timer IC when the input voltage is higher than a predetermined voltage.
13 Citations
3 Claims
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1. A control circuit for vibrating compressors for converting d-c voltage into ac voltage to supply a-c voltage to a vibrating compressor comprising
a MOS-FET transistor for driving said vibrating compressor, a timer IC for generating pulses to switch said MOS-FET transistor, a timer forced-operation circuit for forcibly reversing the output of said timer IC at a timing at which a counter-electromotive voltage generated by said vibrating compressor during the OFF period of said MOS-FET transistor is restored in the vicinity of 0 volts, a driver for driving said MOS-FET transistor based on the output, of said timer IC, said driver including a capacitor for cutting d-c components in a gate of said MOSFET transistor so that said MOS-FET transistor is protected from damage due to malfunction of said control circuit, and a pulse width changing circuit for detecting an input voltage input into said vibrating compressor and lowering said input voltage to said vibrating compressor by changing the pulse width of output pulses of said timer IC when said input voltage is higher than a predetermined voltage which would cause damage to a valve of the vibrating compresor due to an overrun of a piston of the vibrating compressor.
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2. A control circuit for vibrating compressors for converting d-c voltage into a-c voltage to supply ac voltage to a vibrating compressor comprising
a MOS-FET transistor for driving said vibrating compressor, a timer IC for generating pulses to switch said MOS-FET transistor, a timer forced-operation circuit for forcibly reversing the output of said timer IC at a timing at which a counter-electromotive voltage generated by said vibrating compressor during the OFF period of said MOS-FET transistor is restored in the vicinity of 0 volts, a driver for driving said MOS-FET transistor based on the output of said timer IC, said driver including a capacitor for cutting d-c components in a gate of said MOSFET transistor so that said MOS-FET transistor is protected from damage due to malfunction of said control circuit, and a pulse width changing circuit for detecting ambient temperature around said vibrating compressor and lowering an input voltage to said vibrating compressor by changing the pulse width of output pulses of said timer IC when said ambient temperature is lower than a predetermined temperature which would cause damage to a valve of the vibrating compressor due to an overrun of a piston of the vibrating compressor.
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3. A vibrating compressor control circuit for converting d-c voltage into ac voltage and suppling the a-c voltage to a vibrating compressor, the control circuit comprising:
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a transistor for driving the vibrating compressor with on and off periods;
a timer for generating pulses to switch said transistor between said on and off periods;
a timer forced-operation circuit for forcibly reversing a state of one of said pulses of said timer IC at a point where a counter-electromotive voltage generated by the vibrating compressor during one of said off periods has substantially expired;
a pulse width changing circuit for detecting an input voltage supplied to said vibrating compressor and lowering an input power to said vibrating compressor by changing a pulse width of said pulses of said timer when said input voltage is higher than a predetermined voltage which would overrun a piston of the vibrating compressor and damage a valve of the vibrating compressor;
a driver for driving said transistor based on said pulses from said timer, driver including a capacitor for cutting d-c components in a gate of said transistor to protect said transistor from damage due to a malfunction of the control circuit.
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Specification