Switching regulator circuit using magnetic flux-sensing
First Claim
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1. A circuit for use in a switching voltage regulator circuit, the switching voltage regulator circuit having a switching element, control circuitry which turns the switching element on and off, a transformer-coupled output circuit, and a feedback circuit for providing a magnetic flux-sensed feedback signal indicative of the switching voltage regulator circuit output voltage, the circuit comprising:
- a feedback terminal for accepting the magnetic flux-sensed feedback signal;
means connected to the feedback terminal for generating a tracking voltage which tracks an amplified representation of the difference between the voltage waveform on the feedback terminal and an internal reference signal during a portion of each off cycle of the switching element, and for sampling and storing an instantaneous value of the tracking voltage responsive to a transition in the magnetic flux-sensed feedback signal; and
means for varying the on and off cycle of the switching element as a function of the magnitude of the stored instantaneous value of the tracking voltage.
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Abstract
Control circuits for a switching voltage regulator circuit which uses magnetic flux sensing are provided. These circuits can be used to improve output voltage regulation by reducing parasitic effects inherently present in magnetic flux-sensed feedback switching voltage regulator designs.
142 Citations
16 Claims
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1. A circuit for use in a switching voltage regulator circuit, the switching voltage regulator circuit having a switching element, control circuitry which turns the switching element on and off, a transformer-coupled output circuit, and a feedback circuit for providing a magnetic flux-sensed feedback signal indicative of the switching voltage regulator circuit output voltage, the circuit comprising:
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a feedback terminal for accepting the magnetic flux-sensed feedback signal; means connected to the feedback terminal for generating a tracking voltage which tracks an amplified representation of the difference between the voltage waveform on the feedback terminal and an internal reference signal during a portion of each off cycle of the switching element, and for sampling and storing an instantaneous value of the tracking voltage responsive to a transition in the magnetic flux-sensed feedback signal; and means for varying the on and off cycle of the switching element as a function of the magnitude of the stored instantaneous value of the tracking voltage. - View Dependent Claims (2, 3, 4)
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5. A circuit for use in a switching voltage regulator circuit, the switching voltage regulator circuit having a switching element, control circuitry, which turns the switching element on and off, a transformer-coupled output circuit, and a feedback circuit for providing a magnetic flux-sensed feedback signal indicative of the switching voltage regulator circuit output voltage, the circuit comprising:
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a feedback terminal for accepting the magnetic flux-sensed feedback signal; a sampling error amplifier circuit having an input coupled to the feedback terminal and an output, and including circuitry coupled to the input for generating a tracking voltage which tracks an amplified representation of the difference between the voltage waveform on the feedback terminal and an internal reference signal during a portion of each off cycle of the switching element, and circuitry coupled between the tracking voltage generating circuitry and the output for sampling and storing an instantaneous value of the tracking voltage responsive to a transition in the magnetic flux-sensed feedback signal and converting the stored instantaneous value into a control signal at the output; and a switching element control circuit coupled to the output of the sampling error amplifier circuit for varying the on and off cycle of the switching element as a function of the magnitude of the stored instantaneous value of the tracking voltage. - View Dependent Claims (6, 7, 8, 9, 10, 13, 14, 15)
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16. A circuit for use in a switching voltage regulator circuit, the switching voltage regulator circuit having a switching element, control circuitry which turns the switching element on and off, control circuitry which turns the switching element on and off, a transformer-coupled output circuit, and a feedback circuit for providing a magnetic flux-sensed feedback signal indicative of the switching voltage regulator circuit output voltage, the circuit comprising:
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a feedback terminal for accepting the magnetic flux-sensing feedback signal; sampling error amplifier circuit means with an input terminal connected to the feedback terminal and an output terminal connected to a voltage control node for controlling the switching element; sensing means for sensing a signal which is proportional to load current of the switching voltage regulator circuit; and load compensation means connected to the feedback terminal for conducting a current from the feedback terminal in response to an increase in the signal sensed by the sensing means so as to compensate for load-current dependent effects of parasitic impedances in the transformer-coupled output circuit, wherein the sensing means senses the voltage at the voltage control node, which voltage is proportional to the load current of the switching voltage regulator circuit. - View Dependent Claims (11, 12)
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Specification