Circuit to provide a time delay
AssigneeCypress Semiconductor Corporation
InventorsJulian C. Gradinariu, John J. Silver
Life of this patent
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Abstract
A circuit for providing substantially a constant delay of an electrical signal that compensates for voltage, temperature and process variations includes an inverter. A delay cell has an output that is coupled to the inverter. The delay cell includes a charge transistor coupled to a capacitor. A control circuit has an output that is coupled to a gate of the charge transistor. The output has a voltage that is proportional to a trip voltage of the inverter. The delay cell also has a discharge transistor. The control circuit contains a second output that is coupled to a gate of the discharge transistor. The second output has a voltage that is also proportional to the trip voltage of the inverter.
Claims19
A circuit comprising:
- a means for delaying an electrical signal including a capacitor;
- a means for charging the capacitor including an inverter having negative feedback;
- a means for discharging the capacitor;
- a first means for controlling the means for charging using a first resistive element;
- and
- a second means for controlling the means for discharging using a second resistive element.
A control circuit for a delay cell, comprising:
- an inverter having negative feedback;
- an operational amplifier having a non-inverting input coupled to an output of the inverter;
- a mirror control transistor having a gate coupled to an output of the operational amplifier and a source coupled to a power supply voltage and a drain coupled to an inverting input of the operational amplifier;
- and
- a resistor having a first end coupled to a ground and a second end coupled to the drain of the mirror control transistor.
A circuit comprising:
- an inverter;
- a delay cell having an output coupled to the inverter and having a charge transistor coupled to a capacitor;
- and
- a control circuit having an output coupled to a gate of the charge transistor, the output having a voltage that is proportional to a trip voltage of the inverter.
Dependencies are inferred from the claim text.