Electrical circuit for delivering power to consumer electronic devices

A method of operating an electrical circuit for powering electronic devices, the electrical circuit including a voltage reduction circuit cell, a forward converter coupled to the voltage reduction circuit cell for receiving an intermediate power signal from the voltage reduction circuit cell and delivering an output power signal to an electrical device, and a controller for operating the voltage reduction circuit cell and the forward converter, the voltage reduction circuit cell includes an input terminal, an output terminal, a first capacitor, a second capacitor, a switching circuit coupled to the first and the second capacitors, a hold capacitor coupled between the switching circuit and the first and the second capacitors, and the output terminal, the switching circuit including plurality of switching devices including a first switching device for coupling a negative plate of the first capacitor to ground and a second switching device for coupling a negative plate of the second capacitor to ground, the method including the steps of:

• receiving an input power signal at the input terminal;
• the controller determining a gain setting as a function of a voltage level of the input power signal and a desired output voltage level;
• the controller selecting at least one switching device of the plurality of switching devices as a function of the gain setting;
• the controller operating the switching circuit in a charge mode to couple a positive plate of each of the first and the second capacitors to the input terminal and to couple a negative plate of each of the first and the second capacitors to the hold capacitor;
• and
• the controller operating the switching circuit in a discharge mode to deliver the intermediate power signal to the output terminal at the determined gain setting wherein the controller operates the selected at least one switching device in an off-position during each of the charge mode and the discharge mode;
• and
• the controller regulating the forward converter to receive the intermediate power signal from the voltage reduction circuit cell and deliver the output power signal to the electronic device, wherein the forward converter includes a transformer and a transformer regulation switching device coupled to the primary side winding of the transformer, the controller operates the transformer regulation switching device to regulate the transformer to deliver the output power signal at the desired output voltage level, sensing a voltage level of the output power signal;
• delivering a control signal to the plurality of switching devices as a function of the voltage level of the output power signal;
• and adjusting a duty cycle of the control signal to adjust the gain setting to maintain the voltage level of the output power signal at the desired output voltage level.

An apparatus for providing electrical power for use in powering electronic devices, comprising:

• a plurality of capacitors including a first capacitor, a second capacitor, and a hold capacitor;
• a semiconductor chip;
• an input terminal formed on the semiconductor chip and configured to receive an input power signal;
• an output terminal formed on the semiconductor chip and configured to provide an intermediate power signal;
• a plurality of capacitor terminals formed on the semiconductor chip, the plurality of capacitor terminals including a first set of capacitor terminals coupled to the first capacitor, a second set of capacitor terminals coupled to the second capacitor, and a third set of capacitor terminals coupled to the hold capacitor;
• a switching circuit formed on the semiconductor chip, the switching circuit including a plurality of switching devices coupled to the first capacitor, the second capacitor, and the hold capacitor with the plurality of capacitor terminals, the hold capacitor coupled between the switching circuit and the first and the second capacitors, and the output terminal, the plurality of switching devices including a first switching device for coupling a negative plate of the first capacitor to ground and a second switching device for coupling a negative plate of the second capacitor to ground;
• a forward converter coupled to the output terminal of the voltage reduction circuit cell for receiving the intermediate power signal from the voltage reduction circuit cell and delivering an output power signal to an electronic device, the forward converter including a transformer and a transformer regulation switching device coupled to a primary side winding of the transformer;
• an input voltage sensing circuit configured to sense a voltage level of the input power signal;
• and
• a controller coupled to the switching circuit, the input voltage sensing circuit, and the transformer regulation switching device, the controller configured to:
• determine a gain setting as a function of the sensed voltage level of the input power signal and a desired output voltage level;
• select at least one switching device of the plurality of switching devices as a function of the gain setting;
• operate the switching circuit in a charge mode including operating the plurality of switching devices to couple a positive plate of each of the first and the second capacitors to the input terminal and to couple a negative plate of each of the first and the second capacitors to the hold capacitor;
• operate the switching circuit in a discharge mode to deliver the intermediate power signal to the output terminal at the determined gain setting, wherein the controller operates the selected at least one switching device in an off-position during each of the charge mode and the discharge mode;
• and
• operate the transformer regulation switching device to regulate the transformer to receive the intermediate power signal from the voltage reduction circuit cell and deliver the output power signal at the desired output voltage level, at least one of the switching devices configured to regulate a secondary voltage reduction circuit.