Switch power supply controller and control method
AssigneeSilergy Semiconductor Technology (Hangzhou) LTD
InventorJin Jin
Life of this patent
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Abstract
In one embodiment, a switch power supply controller can include: (i) a switch configured to operate in first and second states during each switch cycle; (ii) a switch time regulating circuit that compares a duration of the first state in a present switch cycle against an expected first state duration; (iii) the switch time regulating circuit decreasing a duration of the second state in the present switch cycle when the first state duration is greater than the expected first state duration, to decrease a first state duration for a next switch cycle; and (iv) the switch time regulating circuit being increasing the second state duration in the present switch cycle when the first state duration is less than the expected first state duration, to increase a first state duration for a next switch cycle.
Claims7
A switch power supply controller, comprising:
- a) a switch configured to operate in a first state and a second state during each switch cycle to convert an input signal to an output signal as part of a switch mode power supply;
- b) a switch time regulating circuit configured to compare a duration of said first state of said switch in a present switch cycle against an expected first state duration;
- c) said switch time regulating circuit being configured to decrease a duration of said second state of said switch in said present switch cycle when said first state duration is greater than said expected first state duration, wherein a first state duration for a next switch cycle is decreased due to said second state duration of said present switch cycle being decreased;
- d) said switch time regulating circuit being configured to increase said second state duration in said present switch cycle when said first state duration is less than said expected first state duration, wherein a first state duration for said next switch cycle is increased due to said second state duration of said present switch cycle being increased;
- e) said switch time regulating circuit comprising a reference voltage generating circuit configured to output a reference voltage signal based on said first state duration and said expected first state duration, and a timing circuit configured to control said second state duration to substantially match said reference voltage signal;
- and
- f) said timing circuit comprising a ramp signal generating circuit configured to output a ramp signal at a start time of said second state of said switch, and a comparison circuit configured to compare said ramp signal against said reference voltage signal, and to output a signal to end said second state of said switch when said ramp signal rises to a level of said reference voltage signal.
A method of controlling a switch in a switch power supply, the method comprising:
- a) comparing a duration of a first state of said switch in a present switch cycle against an expected first state duration of said switch, wherein said switch operates in said first state and a second state during each switch cycle;
- b) decreasing a duration of said second state of said switch in said present switch cycle when said first state duration is greater than said expected first state duration, wherein a first state duration for a next switch cycle is decreased due to said second state duration of said present switch cycle being decreased;
- c) increasing said second state duration in said present switch cycle when said first state duration is less than said expected first state duration, wherein a first state duration for said next switch cycle is increased due to said second state duration of said present switch cycle being increased;
- d) providing a ramp signal at a start time of said second state of said switch;
- and
- e) comparing said ramp signal against said reference voltage signal, and providing a signal to end said second state of said switch when said ramp signal rises to a level of said reference voltage signal.
Dependencies are inferred from the claim text.