Differential comparator
AssigneeKabushiki Kaisha Toshiba
InventorYasuo Mizuide
Life of this patent
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Abstract
A differential comparator of the hysteresis type is responsive to a high input difference voltage (V.sub.1 -V.sub.2). The comparator comprises two differential transistors; a hysteresis resistor connected between the emitters of the two transistors; current source means connected to one of the emitters of the two transistors, for determining an emitter current of the two transistors directly and via the hysteresis resistor; and an emitter current controller for controlling the emitter current of the two transistors on the basis of an output current derived from an output terminal. When a voltage difference between the two input terminals reaches a balanced hysteresis voltage value, and therefore no output current flows, the output current is sharply increased in a direction opposite to the preceding direction.
Claims6
A differential comparator of hysteresis type, which comprises:
- (a) a first switching element having a first input terminal to which a first input signal is applied;
- (b) a second switching element having a second input terminal to which a second input signal is applied and an output terminal from which an output signal is outputted;
- (c) a hysteresis resistor connected between the first and second switching elements;
- (d) current source means, for determining bias currents, connected to one switching element directly and to the other switching element via said hysteresis resistor;
- and
- (e) means for increasing/decreasing the bias current in response to said output signal from the output terminal in such a way that when a voltage difference between the first input terminal and the second input terminal reaches a balanced hysteresis voltage value, and therefore no output current flows, the output current is sharply increased in a direction opposite to a preceding direction.
A differential comparator of hysteresis type, which comprises:
- (a) a first transistor having a first input base terminal;
- (b) a second transistor having a second input base terminal and an output collector terminal;
- (c) a hysteresis resistor connected between the emitter terminals of said first and second transistors;
- (d) current source means connected to either emitter terminal of said two transistors for determining an emitter current of said two transistors directly and via said hysteresis resistor;
- and
- (e) means for controlling the magnitude of the emitter current of said two transistors in response to an output collector current derived from the output terminal, in such a way that when a voltage difference between the first input terminal and the second input terminal reaches a balanced hysteresis voltage value, and therefore no output current flows, the output current is sharply increased in a direction opposite to a preceding direction.
Dependencies are inferred from the claim text.