Patent ID: 7772908

Claim:
A delay circuit, comprising: a first delay stage having a supply voltage independent current source and a first capacitor, the first delay configured to delay an input signal by a first delay based on a magnitude current from the supply voltage independent current source and a capacitance of the first capacitor and provide a delayed signal, the supply voltage independent current source comprising: a temperature independent current source configured to generate a temperature independent current, the temperature independent current source comprising: a first constant current source having a first temperature dependency; a second constant current source having a second temperature dependency that is inverse to the first temperature dependency; a first current source coupled to the temperature independent current source and configured to provide a current to the first capacitor based on the temperature independent current from the temperature independent current source; a first current sink coupled to the temperature independent current source and configured to sink a current from the first capacitor based on the temperature independent current from the temperature independent current source; and a second delay stage coupled to the first delay stage and configured to delay the delayed signal by a second delay based on a magnitude of a supply voltage and provide an output signal having a delay relative to the input signal equal to the first and second delays.