Method and apparatus for the generation of voltage pulses
First Claim
1. A method for generating voltage pulses used to control the operation of a switching power supply of the type responsive to synchronizing signals for synchronizing the voltage pulses with a synchronization reference, comprising the steps of:
- (A) generating a voltage pulse having an amplitude which normally increases from a first voltage value to a third voltage value in the absence of one of said synchronization signals;
(B) resetting the amplitude of the voltage pulse generated in step (A) to said first voltage value if said synchronization signal occurs during the increase of amplitude of the voltage pulse generated in step (A) from said first voltage value to said third voltage value;
(C) then, generating a voltage pulse having an amplitude which normally increases from said first voltage value to a second voltage value higher than said third voltage value; and
(D) resetting the amplitude of the voltage pulse generated in step (C) to said first voltage value if said synchronizing signal occurs during the increase of the amplitude of the voltage pulse generated in step (C) from the fourth voltage value to said second voltage value, wherein said fourth voltage value lies between said first and third voltage values.
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Abstract
The present invention relates to a method and apparatus for the generation of voltage pulses for controlling the switching operation in switching power supplies. A voltage increase of a pulse generator is respectively started when reaching a first, lower threshold (A). Resetting of the voltage increase is carried out in free-running mode, when the voltage increase reaches a second (D) or a third (C) threshold lying between the first (A) and the second (D) one. In sync mode, the pulse edges occurring in the synchronization signal (Vsync) effect resetting of the voltage increase. The advantages of the invention lie in the fact that the switching current, occurring at the change form free-running mode to sync mode due to the frequency difference, is minimized and that the generator operates reliably.
12 Citations
29 Claims
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1. A method for generating voltage pulses used to control the operation of a switching power supply of the type responsive to synchronizing signals for synchronizing the voltage pulses with a synchronization reference, comprising the steps of:
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(A) generating a voltage pulse having an amplitude which normally increases from a first voltage value to a third voltage value in the absence of one of said synchronization signals; (B) resetting the amplitude of the voltage pulse generated in step (A) to said first voltage value if said synchronization signal occurs during the increase of amplitude of the voltage pulse generated in step (A) from said first voltage value to said third voltage value; (C) then, generating a voltage pulse having an amplitude which normally increases from said first voltage value to a second voltage value higher than said third voltage value; and (D) resetting the amplitude of the voltage pulse generated in step (C) to said first voltage value if said synchronizing signal occurs during the increase of the amplitude of the voltage pulse generated in step (C) from the fourth voltage value to said second voltage value, wherein said fourth voltage value lies between said first and third voltage values. - View Dependent Claims (2, 3, 4)
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5. A method for generating voltage pulses for controlling the switching operation of a switching power supply, of the type which generates a voltage pulse which starts from a first voltage threshold and normally increases until a higher second voltage threshold is reached whereupon said voltage pulse is reset, and wherein the voltage pulse is synchronized with a synchronization signal, comprising the steps of:
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(A) resetting said voltage pulse, in the absence of the occurrence of said synchronization signal, when said voltage pulse reaches a third voltage threshold, wherein said third voltage threshold lies between said first and second voltage thresholds; (B) resetting the amplitude of said voltage pulse, in the absence of the occurrence of said synchronization signal, when said voltage pulse reaches said second voltage threshold; and
,(C) resetting said voltage pulse in response to the edge of said synchronization signal. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13)
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14. A circuit for generating a series of voltage pulses used to control the operation of a switching power supply of the type responsive to synchronizing signals for synchronizing said voltage pulses with a synchronization reference, and of the type including a bistable circuit for triggering and resetting said voltage pulses, and of the type having a first and second threshold circuit coupled with said bistable circuit for commanding the triggering and resetting said voltage pulses, comprising:
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a third threshold circuit for comparing the magnitude of each one of said voltage pulses with a third reference value, said third reference value being greater than a first reference value associated with said first threshold circuit, and being less than a second reference value associated with said second threshold circuit; a third logic circuit having an output responsive to an edge of said synchronization signal; a first logic circuit responsive to said second and third threshold circuits, and said third logic circuit; and
,a second logic circuit responsive to an edge of an output signal from said third logic circuit output and operative to disable an output of said third threshold circuit when an edge of one of said synchronizing signals occurs and operative to enable the output of said third threshold circuit when the amplitude of one of said series of voltage pulses exceeds the second reference value. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A circuit for generating a voltage pulses used to control the operation of a switching power supply of the type which is responsive to synchronizing signals used to synchronizing said voltage pulses to the synchronizing signals, comprising:
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means for generating said voltage pulses; means responsive to the amplitude of said voltage pulse for sensing when the amplitude of one of said voltage pulses has exceeded each of a plurality of preselected voltage levels; means coupled with said sensing means for detecting the occurrence of an edge of one of said synchronizing signals; and
,means associated with said sensing and detecting means for enabling said generating means to be controlled by said sensing and detecting means. - View Dependent Claims (25, 26, 27, 28, 29)
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Specification