Dual voltage power supply

A power supply comprising:

• first and second outputs providing output voltages of V.sub.1 and V.sub.2, respectively;
• a input voltage source having a positive and negative terminal and providing an input voltage, Vin;
• first and second voltage regulators, the second voltage regulator having first, second, and third terminals;
• a ground terminal;
• and a ground switch having first and second terminals, the first terminal being coupled to the negative terminal of the input voltage source;
• the first voltage regulator being coupled to the positive and negative terminals of the input voltage source and the first output, the first voltage regulator capable of providing an output voltage higher than Vin, and capable of providing an output voltage lower than Vin;
• the first terminal of the second voltage regulator being coupled to the positive terminal of the input voltage source and the second output;
• the second terminal of the second voltage regulator being coupled to the second terminal of the ground switch;
• and the third terminal of the second voltage regulator being coupled to the ground terminal;
• wherein neither the first nor the second voltage regulator includes a transformer.

A method for providing two regulated outputs comprising:

• providing an input voltage source with positive and negative terminals, first and second output terminals providing first and second output voltages, first and second voltage regulators without transformers, a ground, and a ground switch;
• sensing the first output voltage from the first voltage regulator;
• storing energy in the first voltage regulator;
• maintaining the first output voltage at a first predetermined level that is higher than an input voltage provided by the input voltage source when the input voltage is less than the first predetermined level;
• maintaining the first output voltage at the first predetermined level that is lower than an input voltage provided by the input voltage source when the input voltage is greater than the first predetermined level;
• increasing the first output voltage by releasing the energy stored in the first voltage regulator if the first output voltage has dropped below the first predetermined level;
• sensing the voltage at the second output terminal from the second voltage regulator;
• storing energy in the second voltage regulator if the second output voltage has dropped below a second predetermined level by switching the ground switch and thereby coupling the negative terminal of the input voltage source to ground through the second voltage regulator;
• and
• regulating the second output voltage by selectively storing and releasing energy in the second voltage regulator.

A power supply comprising:

• first and second output terminals and a ground terminal, the first and second output terminals providing output voltages of V.sub.1 and V.sub.2, respectively;
• an input voltage source providing an input voltage of V.sub.in ;
• first regulator means coupled between the input voltage source and the first output terminal for converting V.sub.in to V.sub.1, the first regulator means capable of providing an output voltage higher than Vin, and capable of providing an output voltage lower than Vin;
• second regulator means coupled between the input voltage source, the second output terminal, and the ground terminal for converting V.sub.in to V.sub.2, the second regulator means coupled between the input voltage source and the ground terminal such that the input voltage source floats relative to the ground terminal;
• wherein neither the first nor second regulator means includes a transformer.