Clocked Pulse Frequency Modulation Buck DC-to-DC Converter
AssigneeDialog Semiconductor (UK) Limited
InventorMark Childs
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Abstract
A hysteretic mode control circuit within a DC-to-DC converter is configured for varying the current limit that controls the switching interval and duration of a power switching section of the DC-to-DC converter to permit the DC-to-DC converter to manage large changes in output current load of the DC-to-DC converter. The hysteretic mode control circuit has a positive and a negative current limit section that develop a first and a second reference signal for turning on and turning off the first and the second switching device. The first and second reference signals are compared to an output voltage of the power switching section to determine if the first switching device or the second switching device is to be turned on or turned off.
Claims24
A hysteretic mode control circuit within a DC-to-DC converter configured for operating in a continuous mode or a discontinuous mode, the hysteretic mode control circuit comprising:
- a first current limit section configured for determining a first reference limit signal that is used for controlling activation a first switching device of a switching section of the DC-to-DC converter for transferring current to a load device placed at the output of the DC-to-DC converter;
- and
- a pulse width modulation/pulse frequency modulation control circuit configured for receiving the first reference limit signal, configured for comparing an amplitude of the first reference limit signal with a feedback signal from a power switching section of the DC-to-DC converter and configured for generating reset controls for data flip-flops for controlling activation of a first switching device and a second switching device of the DC-to-DC converter;
- wherein the first current limit section and the pulse width modulation/pulse frequency modulation control circuit are configured for varying a current limit that controls the switching interval and duration of a power switching section of the DC-to-DC converter to permit the DC-to-DC converter to manage large changes in output current load of the DC-to-DC converter while in the discontinuous operation mode,
A DC-to-DC converter comprising:
- a hysteretic mode control circuit configured for varying the current limit that controls the switching interval and duration of a power switching section of the DC-to-DC converter to permit the DC-to-DC converter to manage large changes in output current load of the DC-to-DC converter, the hysteretic mode control circuit comprising:
- a first current limit section configured for determining a first reference limit signal that is used for controlling activation a first switching device of a switching section of the DC-to-DC converter for transferring current to a load device placed at the output of the DC-to-DC converter;
- and
- a pulse width modulation/pulse frequency modulation control circuit configured for receiving the first reference limit signal, configured for comparing an amplitude of the first reference limit signal with a feedback signal from a power switching section of the DC-to-DC converter and configured for generating reset controls for data flip-flops for controlling activation of a first switching device and a second switching device of the DC-to-DC converter.
A method for providing hysteretic mode control by supervising a switching interval and duration of a power switching section of a DC-to-DC converter to permit the DC-to-DC converter to manage large changes in output current load of the DC-to-DC converter during a sleep mode, the method comprising the steps of:
- determining a first limit signal proportional to a first limit current flowing in the low pass filter of the DC-to-DC converter;
- comparing an input signal of the low pass filter with the first limit signal;
- resetting a first latching circuit for disabling a first switching device to prevent current from flowing into the low pass filter, when the input signal is greater than a first limit signal voltage;
- and
- allowing current to continue to flow into the low pass filter, when the input signal is less than the first limit signal by not resetting the first latching circuit and not disabling the first switching device.
Dependencies are inferred from the claim text.