Abstract: A switch control circuit (416, 402, 418, 422) and method are provided for transistor-implemented switches (405, 413, 408, 414) of an integrated floating power transfer device (400, 500). The device includes a floating bus (403, 410) driven by a power system which includes a charge pump circuit (419, 408, 414, 420). At least one switch circuit (405, 413) is coupled to the floating bus and the power system for facilitating charging of the floating bus. The switch control circuit (416, 402, 418, 422) includes a level shifting circuit (402) for adjusting a control signal to the at least one switch circuit notwithstanding floating of an input voltage signal thereto to facilitate operation of the switch circuit.

Abstract: A protection circuit and method are provided for a floating power transfer device having one or more switches for controlling charging of a reservoir capacitor across which a load is applied when in use. The protection circuit includes a control circuit, a fault detection circuit and a precharge driver circuit. The control circuit at least partially controls switching of the at least one switch, while the fault detection circuit detects when a fault in the floating power transfer device or the load occurs and sends a fault detect signal to the control circuit in response thereto. The precharge driver circuit, which is enabled by the control circuit responsive to receipt of the fault detect signal, attempts to precharge the reservoir capacitor to a voltage level sufficient for switching of the one or more switches to proceed without damaging the switches.

Abstract: A digital blocking filter and filtering method are provided for a device receiving signals from a transmission line. The transmission line, which may comprise part of a complex bus system, is incompletely terminated, thereby resulting in a reflection signal within the line with transmission of a signal. The digital blocking filter includes a pulse generator for generating a masking pulse timed and of sufficient duration to substantially block at the device the reflection signal, and logic for combining the masking pulse and a received signal from the transmission line, thereby substantially blocking the reflection signal. Circuitry for handling reflection signals of various duration, as well as for substantially blocking a reflection signal on either a falling edge or a rising edge of a state change in the received signal are provided.

Abstract: A digital blocking filter (120) and filtering method are provided for a device (100) receiving signals from a transmission line. The transmission line, which may comprise part of a complex bus system, is incompletely terminated, thereby resulting in a reflection signal within the line with transmission of a signal. The digital blocking filter (120) includes a pulse generator (140) for generating a masking pulse timed and of sufficient duration to substantially block at the device (100) the reflection signal, and logic (130) for combining the masking pulse and a received signal from the transmission line, thereby substantially blocking the reflection signal. Circuitry for handling reflection signals of various duration, as well as for substantially blocking a reflection signal on either a falling edge or a rising edge of a state change in the received signal are provided.

Abstract: A protection circuit and method are provided for a floating power transfer device having one or more switches for controlling charging of a reservoir capacitor across which a load is applied when in use. The protection circuit includes a control circuit (43), a fault detection circuit (33) and a precharge driver circuit (47). The control circuit (43) at least partially controls switching of the at least one switch, while the fault detection circuit (33) detects when a fault in the floating power transfer device or the load occurs and sends a fault detect signal to the control circuit (43) in response thereto. The precharge driver circuit (47), which is enabled by the control circuit (43) responsive to receipt of the fault detect signal, attempts to precharge the reservoir capacitor (35) to a voltage level sufficient for switching of the one or more switches (36, 37) to proceed without damaging the switches (36, 37).

Abstract: A level shifting circuit (20, 30) couples an input current (Iin) from one system to another, isolated, system, by driving a single load (L) via one or more current mirrors of a common type. In a first embodiment (20), two similar type (either N-type or P-type) current mirrors (M1,M2;M3,M4) provide output current (Iout1, Iout2) to a common load. Diodes (D1,D2) are used to split the input current (Iin1, Iin2) between the two current mirrors during normal, non-faulty conditions, and to turn off either one of the two current mirrors during a fault condition to permit proper operation in the presence of a fault. In a second embodiment (30), a single current mirror (M1,M2) mirrors the input current (Iin) to the output load (L), and a pair of diodes (D1,D2) selects which of the isolated systems to use as the power source in the event of a fault.

Abstract: An electromagnetic emission control circuit and method are provided for a power transfer device having a floating bus (214, 215) driven by a power and data system (107, 301, 310, 103). The electromagnetic emission control circuit includes one or more switch control circuits (402, 411) coupled between the floating bus and the power and data system for facilitating charging of the floating bus and for controlling electromagnetic emission from the power transfer device by constraining a slew rate on the floating bus. In one embodiment, the one or more switch control circuits include a first switch control circuit (402) electrically coupled to a high side bus node (214) of the floating bus and a second switch control circuit (411) electrically coupled to a low side bus node (215) of the floating bus. Transfer characteristics of the first and second switch control circuits are tailored to constrain the slew rate on the floating bus.

Abstract: A switch control circuit (416, 402, 418, 422) and method are provided for transistor-implemented switches (405, 413, 408, 414) of an integrated floating power transfer device (400, 500). The device includes a floating bus (403, 410) driven by a power system which includes a charge pump circuit (419, 408, 414, 420). At least one switch circuit (405, 413) is coupled to the floating bus and the power system for facilitating charging of the floating bus. The switch control circuit (416, 402, 418, 422) includes a level shifting circuit (402) for adjusting a control signal to the at least one switch circuit notwithstanding floating of an input voltage signal thereto to facilitate operation of the switch circuit.

Abstract: A digital blocking filter and filtering method are provided for a device receiving signals from a transmission line. The transmission line, which may comprise part of a complex bus system, is incompletely terminated, thereby resulting in a reflection signal within the line with transmission of a signal. The digital blocking filter includes a pulse generator for generating a masking pulse timed and of sufficient duration to substantially block at the device the reflection signal, and logic for combining the masking pulse and a received signal from the transmission line, thereby substantially blocking the reflection signal. Circuitry for handling reflection signals of various duration, as well as for substantially blocking a reflection signal on either a falling edge or a rising edge of a state change in the received signal are provided.

Abstract: A protection circuit and method are provided for a floating power transfer device having one or more switches for controlling charging of a reservoir capacitor across which a load is applied when in use. The protection circuit includes a control circuit, a fault detection circuit and a precharge driver circuit. The control circuit at least partially controls switching of the at least one switch, while the fault detection circuit detects when a fault in the floating power transfer device or the load occurs and sends a fault detect signal to the control circuit in response thereto. The precharge driver circuit, which is enabled by the control circuit responsive to receipt of the fault detect signal, attempts to precharge the reservoir capacitor to a voltage level sufficient for switching of the one or more switches to proceed without damaging the switches.

Abstract: An apparatus and method for improving the speed and accuracy of a feedback amplifier when the primary feedback around the amplifier configuration has been interrupted is provided. An additional feedback loop added to the input stage of the amplifier maintains the circuit response by maintaining the feedback and preventing the saturation of the circuit components.

Abstract: A differential comparator with a hysteresis proportional to the peak value of the input signal. The comparator operates independently of the magnitude of the supply voltage and of the ambient temperature while handling both differential and single-ended inputs and without introducing a delay between the input and the output.

Abstract: An electronic controller for fluorescent lamps includes a DC to AC converter which supplies high frequency current to the lamps and a preconditioner stage which includes a switched mode power supply connected to accept line power and produce a DC input for the DC to AC converter. The switched mode power supply and the DC to AC converter are synchronized to operate in a fixed phase relationship and/or at the same frequency.

Abstract: A controller operates in pre-ignition and ignition phases to obtain stable and reliable control of operation of a half-bridge DC-AC converter in a frequency range which is offset from a resonant frequency of an output circuit which includes a transformer and capacitors and which couples the converter to a fluorescent lamp load. The converter is supplied with a DC voltage from a switched-mode DC-DC supply of a pre-conditioner circuit which responds to a full-wave rectified AC voltage and which is supplied with pulse-width modulated gating pulses from the controller, preferably at a frequency which is the same as that of the converter. The controller monitors signals from the output circuit and pre-conditioner circuits and exercises control to reliable starting and highly efficient lamp operation and to obtain an in-phase proportional relationship of input voltage and current wave forms.

Abstract: A controller operates in pre-ignition and ignition phases to obtain stable and reliable control of operation of a half-bridge DC-AC converter in a frequency range which is offset from a resonant frequency of an output circuit which includes a transformer and capacitors and which couples the converter to a fluorescent lamp load. The converter is supplied with a DC voltage from a switched-mode DC-DC supply of a pre-conditioner circuit which responds to a full-wave rectified AC voltage and which is supplied with pulse-width modulated gating pulses from the controller, preferably at a frequency which is the same as that of the converter. The controller monitors signals from the output circuit and pre-conditioner circuits and exercises control to reliable starting and highly efficient lamp operation and to obtain an in-phase proportional relationship of input voltage and current waveforms.

Abstract: A circuit switches with a hysteresis defined by separately controllable thresholds which can be made largely independent of temperature and fabrication conditions. The circuit contains a pair of differential portions (21 and 22) and an arithmetic component (24). The hysteresis is introduced into the circuit by using positive feedback to control the position of a switch (23) in such a manner as to change the transconductance of the circuit as it is switching.