Universal AC adapter
A method and apparatus for adaptively configuring an array of voltage transformation modules is disclosed. The aggregate voltage transformation ratio of the adaptive array is adjusted to digitally regulate the output voltage for a wide range of input voltages. An integrated adaptive array having a plurality of input cells, a plurality of output cells, or a plurality of both is also disclosed. The input and output cells may be adaptively configured to provide an adjustable transformer turns ratio for the adaptive array or in the case of an integrated VTM, an adjustable voltage transformation ratio for the integrated VTM. A controller is used to configure the cells and provide digital regulation of the output. A converter having input cells configured as a complementary pair, which are switched out of phase, reduces common mode current and noise. Series connected input cells are used for reducing primary switch voltage ratings in a converter and enabling increased operating frequency or efficiency. An off-line auto-ranging power supply topology is disclosed. An auto-ranging converter module (“ACM”) includes 2 or more input cells magnetically coupled to an output cell providing auto-ranging, isolation, and voltage transformation. The ACM converts a rectified line voltage to a low DC bus voltage. The topology allows regulation and power factor correction to be provided at a low voltage increasing energy density and efficiency and reducing cost. A fully integrated PCM may also include a hold-up circuit, a DC input, and a power regulator with or without power factor correction. A PCM with PFC may combine the hold-up and smoothing capacitors for further increases in power density. A universal AC adapter architecture is shown using a unipolar bus to distribute power to one or a plurality of stationary or mobile electronic devices.
1. A method of converting power from an AC source at a source voltage for delivery to a load at a DC load voltage, where the source voltage may vary between a high line voltage and a low line voltage in a normal operating range, comprising:
providing DC-DC voltage transformation and isolation in a first power conversion stage, the first stage having a converter array (CA) input for receiving power from the source and a CA output for delivering a galvanically isolated unregulated AC adapter module (UAAM) voltage;
providing power regulation in a second power conversion stage having a power regulation (PR) input for receiving power from the CA output of the first stage, regulation circuitry, and a PR output for delivering power to the load; the regulation circuitry being adapted to maintain the load voltage within a regulation range while the PR input voltage remains within a normal operating range.
2. The method of claim 1 wherein the providing DC-DC voltage transformation and isolation further comprises providing an integrated adaptive converter array having a first input cell and a second input cell, each input cell having a respective number, Px, of turns, an output cell having a respective number, Sx, of turns, magnetic coupling between the turns to form a transformer common to the first and second input cells and the output cell; and further comprising:
configuring the input cells in a parallel connection for operation at the low line voltage and in a series connection for operation at the high line voltage.
3. The method of claim 1 wherein the providing DC-DC voltage transformation and isolation further comprises:
providing an array of two or more voltage transformation modules (VTMs), each VTM having an input, an output, and a substantially fixed voltage transformation ratio, K=Vout/Vin, over the normal operating range, where Vin is the voltage across the respective VTM input and Vout is the voltage across the respective VTM output, and providing isolation between its input and its output; and
configuring the inputs of the VTMs in a parallel connection for operation at the low line voltage and in a series connection for operation at the high line voltage.
4. The method of claim 1 , 2 , or 3 further comprising providing first stage circuitry for performing the first power conversion stage in a self-contained adapter module having terminals for connecting to the AC source and the PR input and providing second stage circuitry for performing the second stage power conversion external to the adapter module.
5. The method of claim 4 wherein the load comprises an electronic device and further comprising providing the second stage circuitry in the electronic device.
6. The method of claim 1 further comprising providing a DC input for receiving power from an external DC source directly coupled to the second power conversion stage.
7. The method of claim 1 , 2 , or 3 further comprising providing filtering of the galvanically isolated UAAM voltage.