Automatic zero voltage switching mode controller
First Claim
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1. An automatic zero voltage switching mode controller comprising:
- a first timer operable at a first time interval;
a second timer operable at a second time interval;
a switching control signal output circuit configured to selectively drive a switching stage of a switch mode power converter with zero voltage switching in accordance with one of the first time interval and the second time interval;
a controller coupled with the second timer, where the controller is configured to automatically adjust the second time interval of the second timer to adjust a zero voltage switching dead-time based on a measured parameter indicative of a predetermined range of alternating current flow to a load; and
a counter configured to disable the second timer in response to the measured signal being indicative of a current flow to the load greater than a predetermined amount.
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Abstract
A switching DC to AC power converter includes an automatic zero voltage switching (ZVS) mode controller. The automatic zero voltage switching mode controller may adjust a ZVS dead-time in accordance with a range of load currents being supplied by the power converter that range from quiescent conditions to a predetermined loading level of the power converter. The variable ZVS dead-time may be larger nearer to quiescent conditions, and become progressively smaller as load currents increase. Outside a predetermined range of load currents, the variable ZVS dead-time may be disabled or minimized.
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Citations
17 Claims
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1. An automatic zero voltage switching mode controller comprising:
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a first timer operable at a first time interval; a second timer operable at a second time interval; a switching control signal output circuit configured to selectively drive a switching stage of a switch mode power converter with zero voltage switching in accordance with one of the first time interval and the second time interval; a controller coupled with the second timer, where the controller is configured to automatically adjust the second time interval of the second timer to adjust a zero voltage switching dead-time based on a measured parameter indicative of a predetermined range of alternating current flow to a load; and a counter configured to disable the second timer in response to the measured signal being indicative of a current flow to the load greater than a predetermined amount. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An automatic zero voltage switching mode controller comprising:
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an input processing circuit configured to receive a pulse width modulation signal; a timer circuit configured to selectively impose a zero voltage switching dead time having a variable time period on the pulse width modulation signal; and a controller configured to receive a measured parameter indicative of a load current of a power converter, the controller coupled with the timer circuit and further configured to dynamically adjust the variable time period to a maximum time period in response to the load current being at quiescent conditions, and the controller further configured to progressively reduce the variable time period in accordance with increased load current, where the input processing circuit is configured to disable the dynamically adjustable variable time period in response to the load current exceeding a predetermined magnitude. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method of controlling automatic zero voltage switching, the method comprising:
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receiving a pulse width modulation signal; sensing a measured parameter indicative of a load current of a power converter; adjusting a variable zero voltage switching dead time in accordance with a magnitude of the load current; inserting the variable zero voltage switching dead time into the pulse width modulation signal; and disabling the variable zero voltage switching dead time when the load current exceeds a predetermined magnitude. - View Dependent Claims (15, 16, 17)
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Specification