Powered wet-shaving razor

1. An apparatus comprising:

a load; and

a voltage conversion system coupled to the load and to a voltage source, the voltage conversion system configured to transform a variable voltage provided by the voltage source into a constant operating voltage for driving the load; wherein the voltage conversion system comprises:

a voltage monitor coupled to the voltage source for measuring the variable voltage;

a capacitor;

an inductor in series with the voltage source, the inductor and capacitor being arranged such that voltage across the capacitor depends upon voltage across the inductor;

an oscillator for controlling the voltage across the inductor; and

control logic coupled to the voltage monitor, the control logic being configured to control an output of the voltage conversion system on the basis of a measurement of the variable voltage; and

an external switch for starting the oscillator, thereby causing the voltage across the capacitor to be sufficient to initialize the control logic.

2. The apparatus of claim 1 , wherein the control logic is configured to control the output of the voltage conversion system to cause the constant operating voltage to be less than the variable voltage.

3. The apparatus of claim 2 , wherein the voltage conversion system comprises

a pulse width modulator having a duty cycle that varies in response to a control signal,

and wherein the control logic is configured to cause a control signal to be provided to the pulse width modulator, the control signal being dependent on a measurement of the variable voltage.

4. The apparatus of claim 1 , wherein the control logic is configured to control the output of the voltage conversion system to cause the constant operating voltage to be greater than the variable voltage.

5. The apparatus of claim 1 , wherein the control logic is configured to be powered by the voltage across the capacitor.

6. The apparatus of claim 1 , further comprising a decoupling circuit in communication with the switch and the control logic, the decoupling circuit being configured to transfer control of the oscillator from the external switch to the control logic in response to detecting that the voltage across the capacitor is sufficient to initialize the control logic.

7. The apparatus of claim 6 , wherein the decoupling circuit is configured to enable the control logic to determine a state of the external switch.

8. The apparatus of claim 1 , further comprising a unidirectional conductor between the capacitor and the inductor.

9. The apparatus of claim 8 , wherein the unidirectional conductor comprises a diode.

10. The apparatus of claim 8 , wherein the unidirectional conductor comprises a transistor having a control terminal controlled by an RC circuit.

11. The apparatus of claim 1 , further comprising an indicator for providing a user-detector signal indicative of the variable voltage having reached an operating threshold.

12. The apparatus of claim 1 , wherein the control logic is configured to provide a low-power signal in response to detecting that the variable voltage has reached an operating threshold.

13. The apparatus of claim 1 , wherein the control logic is configured to disable operation of the razor in response to detecting that the variable voltage has reached a deep-discharge threshold.

14. An apparatus comprising:

a load; and

a voltage conversion system coupled to the load and to a voltage source, the voltage conversion system configured to transform a variable voltage provided by the voltage source into a constant operating voltage for driving the load; and

an external switch for starting the voltage conversion system.

15. The apparatus of claim 14 , wherein the voltage conversion system comprises:

a voltage monitor coupled to the voltage source for measuring the variable voltage; and

control logic coupled to the voltage monitor, the control logic being configured to control an output of the voltage conversion system on the basis of a measurement of the variable voltage.

16. The apparatus of claim 15 , wherein the voltage conversion system further comprises:

a capacitor;

an inductor in series with the voltage source, the inductor and capacitor being arranged such that voltage across the capacitor depends upon voltage across the inductor; and

an oscillator for controlling the voltage across the inductor.

17. The apparaturs of claim 16 , wherein the external switch starts the oscillator, thereby causing the voltage across the capacitor to be sufficient to initialize the control logic.

18. The apparatus of claim 14 , wherein the control logic is configured to do at least one of the following:

control the output of the voltage conversion system to cause the constant operating voltage to be greater than the variable voltage,

be powered by the voltage across the capacitor, and

control the oscillator, thereby controlling the voltage across the capacitor.