Claims
- 1. In a current control circuit enabled by a load actuation signal and comprising switch means operative to actuate an inductive load by increasing the current thereto above a first current level and to thereafter alternatively connect and disconnect a power supply to the load so as to maintain load actuation with current in a range between a second current level and a third current level, each less than said first current level;
- (a) load current sense means comprising a first sense resistor in series with said inductive load and second sense resistor connected in parallel with said first sense resistor;
- (b) reference means providing at least two reference voltages representing two of said first, second, and third current levels;
- (c) comparator means having a sense input coupled to said second sense resistor, a reference input coupled to said reference means, and an output coupled to the switch means, said comparator means adapted to generate a first comparator output level when a sense voltage at said sense input is a greater magnitude than a reference voltage at said reference input and a second comparator output level when said sense voltage is less than the magnitude of the reference voltage at said reference input;
- (d) flip-flop means coupled to said comparator means and to circuit means responsive to the attainment of said first current level, said flip-flop means comprising variable current source means coupled in series with said second sense resistor and operative to change the current therethrough in response to said attainment of said first current level.
- 2. The current control circuit of claim 1 wherein said circuit means responsive to the attainment of said first current level comprises one of said comparator means outputs and the switch means.
- 3. The current control circuit of claim 1 or 2 wherein said flip-flop means is operative to generate a first flip-flop output level in response to the commencement of the load actuation signal and a second flip-flop output level in response to the attainment of said first current level.
- 4. The current control circuit of claim 1 or 2 wherein said reference means comprises a feedback resistor coupling said comparator means output and said comparator means reference input and operative to generate thereat one of said two reference levels when said comparator means generates one of said first and second comparator output levels and the other of said two reference levels when said comparator means generates the other of said first and second comparator output levels.
Parent Case Info
This is a continuation of application Ser. No. 881,328, filed Feb. 27, 1978, now abandoned.
US Referenced Citations (7)
Continuations (1)
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Number |
Date |
Country |
Parent |
881328 |
Feb 1978 |
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