VALLEY TO VALLEY SWITCHING IN QUASI-RESONANT MODE FOR DRIVER
First Claim
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1. A method for controlling power delivered to a load, the method comprising:
- determining whether or not to adjust a turn-on time of a switch from a first time associated with a first voltage valley in an oscillating voltage at a node of the switch so that an average amount of current flowing through the load or an average amount of voltage at the load is approximately equal to a target current load level or a target voltage load level;
determining a second time associated with a second voltage valley in the oscillating voltage;
adjusting gradually the turn-on time of the switch from the first time to the second time, through an intermediate time associated with a non-valley voltage in the oscillating voltage at the node of the switch, based on the determination to adjust the turn-on time; and
adjusting gradually one or more switch operational parameters for the switch to keep the amount of power delivered to the load approximately constant during the gradual adjustment of the turn-on time of the switch from the first time to the second time.
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Abstract
Techniques are described to adjust the time when a switch is turned on from the time of one voltage valley to the time of another voltage valley for controlling an average load current or average load voltage. In some examples, the adjustment is instantaneous, and in some examples, the adjustment is gradual. Both of these example techniques provide for high switching efficiency of the switch.
18 Citations
20 Claims
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1. A method for controlling power delivered to a load, the method comprising:
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determining whether or not to adjust a turn-on time of a switch from a first time associated with a first voltage valley in an oscillating voltage at a node of the switch so that an average amount of current flowing through the load or an average amount of voltage at the load is approximately equal to a target current load level or a target voltage load level; determining a second time associated with a second voltage valley in the oscillating voltage; adjusting gradually the turn-on time of the switch from the first time to the second time, through an intermediate time associated with a non-valley voltage in the oscillating voltage at the node of the switch, based on the determination to adjust the turn-on time; and adjusting gradually one or more switch operational parameters for the switch to keep the amount of power delivered to the load approximately constant during the gradual adjustment of the turn-on time of the switch from the first time to the second time. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A driver system for controlling power delivered to a load, the driver system comprising:
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a transformer comprising a primary side that includes a first coil and a secondary side that includes a second coil, wherein the load is connected to the second coil; a switch coupled to the first coil; and a driver coupled to the switch and configured to; determine whether or not to adjust a turn-on time of the switch from a first time associated with a first voltage valley in an oscillating voltage at a node of the switch so that an average amount of current flowing through the load or an average amount of voltage at the load is approximately equal to a target current load level or a target voltage load level; determine a second time associated with a second voltage valley in the oscillating voltage; adjust gradually the turn-on time of the switch from the first time to the second time, through an intermediate time associated with a non-valley voltage in the oscillating voltage at the node of the switch, based on the determination to adjust the turn-on time; and adjust gradually one or more switch operational parameters for the switch to keep the amount of power delivered to the load approximately constant during the gradual adjustment of the turn-on time of the switch from the first time to the second time. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A driver for controlling power delivered to a load, the driver comprising:
a controller configured to; determine whether or not to adjust a turn-on time of a switch from a first time associated with a first voltage valley in an oscillating voltage at a node of the switch so that an average amount of current flowing through the load or an average amount of voltage at the load is approximately equal to a target current load level or a target voltage load level; determine a second time associated with a second voltage valley in the oscillating voltage; adjust gradually the turn-on time of the switch from the first time to the second time, through an intermediate time associated with a non-valley voltage in the oscillating voltage at the node of the switch, based on the determination to adjust the turn-on time; and adjust gradually one or more switch operational parameters for the switch to keep the amount of power delivered to the load approximately constant during the gradual adjustment of the turn-on time of the switch from the first time to the second time. - View Dependent Claims (15, 16, 17, 18, 19, 20)
Specification