Toko America, Inc.

Toko, Inc.

Brian P Erisman

A MOSFET driven integrated circuit or other peripheral circuit interfaced to a controller that operates on the primary side of a DC to DC converter having a high input voltage relative to the supply voltage powering both the controller and the MOSFET driver or other peripheral circuit is controlled by an under-voltage lockout circuit to transition from a standby mode to a normal operating mode of the MOSFET driver or other peripheral circuit only when the supply voltage is sufficient to sustain normal operation and the driver or other peripheral circuit senses activity at an input that indicates that the controller has previously transitioned from a standby mode to a normal operating mode.

Drive signal controlled under-voltage lockout circuit

A signal isolator circuit employing a pulse transformer overcomes the disadvantages of both prior art opto-coupler and pulse transformer signal isolator circuits by employing an active signal retrieval circuit which, in a higher accuracy configuration, repetitively performs the following steps on the electrical side of the pulse transformer where the signal information is required: 1) drives a current pulse into the pulse transformer; 2) samples or detects the voltage across the pulse transformer after it has been stabilized; 3) holds or stores the sampled voltage for a full cycle of operation; and, if necessary, 4) filters the sampled signal. On the other electrical side of the pulse transformer, the retrieval circuitry is configured such that when the pulse transformer is being driven by the current pulse, the voltage will be clamped by the source signal reset. In a lower accuracy configuration, the signal retrieval circuit of the present invention performs the same steps set forth above with the exception that, rather than sampling the voltage across the pulse transformer, the reflected impedance is detected as being either high or low, by some quantitative measure, and the detector output will be set to either a high or low voltage corresponding to the detected impedance.

Pulse transformer circuit for isolating electrical signals

A MOSFET driver integrated circuit or other peripheral circuit interfaced to a controller that operates on the primary side of a DC to DC converter having a high input voltage relative to the supply voltage powering both the controller and the MOSFET driver or other peripheral circuit is controlled by an under-voltage lockout circuit to transition from a standby mode to a normal operating mode of the MOSFET driver or other peripheral circuit only when the supply voltage is sufficient to sustain normal operation and the driver or other peripheral circuit senses activity at an input that indicates that the controller has previously transitioned from a standby mode to a normal operating mode.

Drive signal controlled undervoltage lockout circuit

A controller for a two-switch buck-boost converter accomplishes one-at-a-time switch control by simultaneously employing an analog error signal to control one drive output and an analog inversion of that error signal, with respect to a voltage that is equal to the voltage excursion limit of a timing ramp signal, to control the other drive output. In a second embodiment of the invention, a controller employs a comparator to compare an analog error signal against a given voltage excursion limit of a timing ramp signal to perform the functions of determining which of two drive outputs is to be enabled to be modulated and of modifying the voltage excursion limits of the timing ramp signal such that the voltage excursion limit compared by the comparator is switched between two different voltage excursion limits.

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Colorado Springs, CO, United States of America

Brian P Erisman