Constant voltage discharge device

1. A constant voltage discharge device for coupling between a power source and a power supply of an electronic circuit, the device comprising:

an input;

an output operatively coupled to the input;

a storage capacitor;

a first DC/DC voltage converter that receives an input current at a first voltage level and generates an output current at a second voltage level to charge the storage capacitor;

a second DC/DC voltage converter to discharge the storage capacitor and provide an output voltage level at the output below the second voltage level to provide temporary power to the power supply of the electronic circuit when power between the power source and the power supply is interrupted; and

a feedback circuit operatively coupled between the second DC/DC voltage converter and the output to monitor voltage between the power source and the power supply via the output,

such that, when power at the input fails or shorts, the first DC/DC voltage converter turns off, and the second DC/DC voltage converter switches on, draining the storage capacitor to generate the output voltage level.

2. The constant voltage discharge device of claim 1 , wherein the feedback circuit comprises:

first and second resistors operatively coupled between the output and a reference voltage; and

a feedback path operatively coupled between the first and second resistors to provide a sampled voltage from between the first and second resistors to the second DC/DC voltage converter.

3. The constant voltage discharge device of claim 1 , wherein the second DC/DC voltage converter provides the output voltage level at the output below the first voltage level to provide temporary power to the power supply of the electronic circuit.

4. The constant voltage discharge device of claim 1 , further comprising a second feedback circuit operatively coupled to the first DC/DC voltage converter to monitor voltage of the storage capacitor.

5. The constant voltage discharge device of claim 1 , further comprising a current-limiting resistor operatively coupled between the first DC/DC voltage converter and the storage capacitor.

6. A circuit for providing temporary power to a power supply of an electronic circuit when power between a power source and the power supply is interrupted, the circuit comprising:

a storage capacitor;

a first voltage converter that receives an input current at a first voltage level and generates an output current at a second voltage level to charge the storage capacitor;

a current-limiting resistor operatively coupled between the first voltage converter and the storage capacitor;

a feedback loop to monitor voltage between the power source and the power supply; and

a second voltage converter to discharge the storage capacitor and provide an output voltage level below the second voltage level to provide temporary power to the power supply of the electronic circuit;

wherein the feedback loop comprises a feedback path providing a sampled voltage to the second voltage converter, whereby when power at the input fails or shorts, the first voltage converter turns off and the second voltage converter switches on draining the storage capacitor to generate the output voltage level.

7. The constant voltage discharge device of claim 6 , wherein the feedback loop further comprises first and second resistors operatively coupled between an output of the circuit and a reference voltage, wherein the feedback path is operatively coupled between the first and second resistors, and wherein the sampled voltage is from between the first and second resistors.

8. The constant voltage discharge device of claim 6 , wherein the second voltage converter provides the output voltage level at the output below the first voltage level to provide temporary power to the power supply of the electronic circuit.

9. The constant voltage discharge device of claim 6 , further comprising a second feedback circuit operatively coupled to the first voltage converter to monitor a voltage of the storage capacitor.

10. A method for supplying a temporary power to a power supply of an electronic circuit when power between a power source and the power supply is interrupted, the method comprising:

receiving an input current at a first voltage level from the power source and generating an output current at a second voltage level with a first DC/DC voltage converter to charge a storage capacitor;

monitoring voltage between the power source and the power supply;

discharging the storage capacitor and providing an output voltage level to the power supply below the second voltage level with a second DC/DC voltage converter to provide temporary power to the power supply of the electronic circuit when voltage between the power source and the power supply decreases below a threshold; and

when power at the input fails or shorts, turning off the first DC/DC voltage converter, switching on the second DC/DC voltage converter, and draining the storage capacitor to generate the output voltage level.

11. The method of claim 10 , wherein monitoring comprises providing a feedback circuit including:

first and second resistors series operatively coupled between the power source and a reference voltage; and

a feedback path operatively coupled between the first and second resistors to provide a sampled voltage from between the first and second resistors to the second DC/DC voltage converter.

12. The method of claim 10 , wherein the second DC/DC voltage converter provides the output voltage level to the power supply below the first voltage level to provide temporary power to the power supply of the electronic circuit.

13. The method of claim 10 , further comprising operatively coupling a second feedback circuit to the first DC/DC voltage converter to monitor a voltage of the storage capacitor.

14. The method of claim 10 , further comprising operatively coupling a current-limiting resistor between the first DC/DC voltage converter and the storage capacitor.