Abstract: A power supply controller controls power supplies for power-up and/or shut-down in a desired sequence. An input voltage for the power supplies powers, and is monitored by, a first control unit having outputs for enabling the power supplies. A second control unit monitors output voltages of the power supplies, and an isolating signal coupler couples signals in both directions between the first and second control units. The second control unit is powered in an isolated manner from the input voltage, conveniently via a transformer constituting the signal coupler. The control units together respond to the monitored voltages for enabling the power supplies in accordance with the desired sequence, information for which can be stored in a non-volatile store. The second control unit can also include enable outputs isolated from the input voltage, and trim outputs for adjusting the monitored voltages.

Abstract: A power supply controller controls power supplies for power-up and/or shut-down in a desired sequence. An input voltage for the power supplies powers, and is monitored by, a first control unit having outputs for enabling the power supplies. A second control unit monitors output voltages of the power supplies, and an isolating signal coupler couples signals in both directions between the first and second control units. The second control unit is powered in an isolated manner from the input voltage, conveniently via a transformer constituting the signal coupler. The control units together respond to the monitored voltages for enabling the power supplies in accordance with the desired sequence, information for which can be stored in a non-volatile store. The second control unit can also include enable outputs isolated from the input voltage, and trim outputs for adjusting the monitored voltages.

Abstract: An isolating coupling arrangement couples signals in both directions via a transformer between first and second (or more) units each having differential signal transmit buffers and receivers. A diode bridge and capacitor produce an isolated power supply voltage for the second unit from signals coupled from the first unit via the transformer. The diode bridge can use intrinsic diodes of CMOS output circuits of the transmit buffers, which can be controlled synchronously using a phase locked loop responsive to signals coupled from the first unit via the transformer. A supply voltage for the first unit can be increased to compensate for voltage drops of the diode bridge on start-up prior to the synchronous operation. A resistor in parallel with a diode of the bridge provides an asymmetrical load to create a DC component of transformer magnetizing current to eliminate oscillations during signal gaps.

Abstract: A circuit controls the low frequency load currents drawn by components of telecommunications systems. The circuit includes a power converter, a first sense circuit, a second sense circuit, a comparator, and a power converter control circuit. The power converter control circuit controls the power converter's duty cycle in accordance with the input signal compared to a reference. In this manner, the low frequency load currents may be easily and economically controlled.

Abstract: In a DC converter, a transformer has a first winding coupled in series with a first capacitor and a first switch between a first pair of terminals, and a second winding coupled in series with a second capacitor and an inductor between a second pair of terminals. A second switch is coupled in parallel with the series-connected first winding and first capacitor. A third switch or diode is coupled in parallel with the series-connected second winding and second capacitor. The capacitors provide energy transfer in either direction via the transformer. Leakage inductance of the transformer facilitates zero voltage switching conditions, and the transformer core is reset in each cycle by charge balancing between the capacitors. The switches can comprise AC switches. The transformer can be an autotransformer.

Abstract: A plurality of power sources (26) supply power to a plurality of loads (24) via a distribution network (20, 22). Voltage is sensed at one or more points (28) in the network to provide a closed loop for regulating current or power supplied by the power sources, thereby allowing for voltage drops due to resistance of the distribution network. The loads may be low voltage integrated circuit devices on a printed circuit board (10), the distribution network may comprise power and ground planes of the board, and the power sources may be switch mode power converters on the board and providing regulated output currents.

Abstract: A pulse modulation arrangement for a switch mode regulator includes a frequency controlled oscillator. A counter is enabled by a clock signal for the regulator to count a controlled number of output pulses of the oscillator and thereby produce a pulse modulation signal. The oscillator frequency and count number are controlled by digital and optionally analog feed forward and/or feedback control signals of the regulator. The oscillator can comprise binary weighted current sources and/or capacitors, or delay elements.

Abstract: DC-DC converters have high side and rectifier circuits, and output capacitor. High side circuit connects between input voltage and output voltage, and has primary winding and auxiliary section that operate transformer properly. Auxiliary may have switches or combination of switches and capacitors. High side circuit converts electrical into magnetic energy through transformer primary, which is then transferred to output through rectifier circuit. It also transfers energy directly to output voltage. Converters have high efficiency, fast dynamic response and high current output. Converters can have large duty cycle and large input voltage and output voltage conversion ratio. High side circuit can be half-bridge, full-bridge or forward converter. Rectifier uses inductors on either side of the secondary, and diodes or synchronous rectifiers, to rectify output voltage. Multi-phase interleaved circuits utilize shared switches to reduce size.

Abstract: In a DC converter, a transformer has a first winding coupled in series with a first capacitor and a first switch between a first pair of terminals, and a second winding coupled in series with a second capacitor and an inductor between a second pair of terminals. A second switch is coupled in parallel with the series-connected first winding and first capacitor. A third switch or diode is coupled in parallel with the series-connected second winding and second capacitor. The capacitors provide energy transfer in either direction via the transformer. Leakage inductance of the transformer facilitates zero voltage switching conditions, and the transformer core is reset in each cycle by charge balancing between the capacitors. The switches can comprise AC switches. The transformer can be an autotransformer.

Abstract: In a power factor corrected AC-to-DC power supply system, a DC-to-DC power converter is coupled to the output of an AC-to-DC power converter in order to produce a regulated DC output signal from a rectified AC input signal. The AC-to-DC power converter and the DC-to-DC power converter each includes a switch for controlling the operation of their respective power converter. The AC-to-DC converter includes an inductor. The system provides power factor correction for minimizing harmonic distortion by including a controller that receives the regulated DC output voltage as a feedback signal, and in response, produces a series of drive pulses having predetermined constant duty cycle. These pulses are simultaneously fed to each switch, to operate the respective converters alternately between ON and OFF states.

Abstract: An asymmetrical pulse width modulated resonant DC--DC converter exhibiting improved zero voltage switching characteristics is disclosed. The converter includes a chopper circuit to convert the DC input voltage to a high frequency AC voltage which, in turn, is fed to a high frequency transformer whose secondary AC is rectified and filtered to produce a stable DC output. A compensation network is placed between the input and the chopper circuit which provides zero voltage switching of the converter over a wide input voltage range.

Abstract: A flyback converter has a main switch coupling a primary winding of a transformer between supply terminals, a duty cycle of the main switch controlling an output of the converter derived from a secondary winding of the transformer. Soft (zero voltage) switching of the main switch is facilitated by a snubber capacitor in parallel with the main switch. An auxiliary circuit coupled in parallel with the snubber capacitor and main switch includes a series-connected auxiliary switch, capacitor, and inductor coupled via another inductor to a full wave rectifier arrangement for recovering energy from the snubber capacitor. Resonant circuits provided by the auxiliary circuit facilitate soft switching of the auxiliary switch for low power loss and high frequency operation. The switches can be MOSFETs with reverse-poled diodes in parallel with their drain-source paths.