Abstract: An apparatus includes a first auxiliary switch connected to a positive connection of a switching leg of a DC-to-DC converter. The switching leg includes a first main switch and a second main switch connected at a main switch midpoint. A second auxiliary switch is connected between a negative connection of the switching leg and the first auxiliary switch. A connection point between the first and second auxiliary switches is an auxiliary midpoint. An auxiliary inductor connects the auxiliary midpoint and the main switch midpoint. The main switch midpoint is also connected to other converter elements. The first and second main switches include a first capacitance a second capacitance. A switch regulation module regulates the first and second auxiliary switches to control current in the auxiliary inductor to provide or remove charge from the first and second capacitances to induce zero voltage switching for the first and second main switches.

Abstract: An apparatus for zero voltage switching is disclosed. A system and method also perform the functions of the apparatus. The apparatus includes an MCT region module that defines a minimum current trajectory (“MCT”) for operation between a maximum positive power output to a maximum negative power output of a bidirectional DC-to-DC converter. The converter includes a dual active bridge series resonant converter. The MCT defines a boundary between a zero voltage switching (“ZVS”) region and a hard switching region. The apparatus includes an offset module that defines an offset to the MCT, the offset in the ZVS region, and an MCT control module that adjust switching of switches of the converter to maintain operation of the converter in the ZVS region between the maximum positive power output to a maximum negative power output along a trajectory defined by the MCT and the offset.

Abstract: An apparatus includes a voltage regulation module that controls output voltage of a bidirectional DC to DC converter to an output voltage reference over an output current range between a positive power reference and a negative power reference. A positive power regulation module controls output power of the converter to the positive power reference over a positive constant power range between the output voltage reference and a positive output current reference. A negative power regulation module controls output power of the converter to the negative power reference over a constant power range between the output voltage reference and a maximum negative power limit, and a constant current module limits output current to a positive output current reference in a range between a minimum output voltage and output power of the converter reaching the positive power reference.

Abstract: An apparatus for zero voltage switching is disclosed. A system and method also perform the functions of the apparatus. The apparatus includes an MCT region module that defines a minimum current trajectory (“MCT”) for operation between a maximum positive power output to a maximum negative power output of a bidirectional DC-to-DC converter. The converter includes a dual active bridge series resonant converter. The MCT defines a boundary between a zero voltage switching (“ZVS”) region and a hard switching region. The apparatus includes an offset module that defines an offset to the MCT, the offset in the ZVS region, and an MCT control module that adjust switching of switches of the converter to maintain operation of the converter in the ZVS region between the maximum positive power output to a maximum negative power output along a trajectory defined by the MCT and the offset.

Abstract: An apparatus includes a first auxiliary switch connected to a positive connection of a switching leg of a DC-to-DC converter. The switching leg includes a first main switch and a second main switch connected at a main switch midpoint. A second auxiliary switch is connected between a negative connection of the switching leg and the first auxiliary switch. A connection point between the first and second auxiliary switches is an auxiliary midpoint. An auxiliary inductor connects the auxiliary midpoint and the main switch midpoint. The main switch midpoint is also connected to other converter elements. The first and second main switches include a first capacitance a second capacitance. A switch regulation module regulates the first and second auxiliary switches to control current in the auxiliary inductor to provide or remove charge from the first and second capacitances to induce zero voltage switching for the first and second main switches.

Abstract: An apparatus includes a voltage regulation module that controls output voltage of a bidirectional DC to DC converter to an output voltage reference over an output current range between a positive power reference and a negative power reference. A positive power regulation module controls output power of the converter to the positive power reference over a positive constant power range between the output voltage reference and a positive output current reference. A negative power regulation module controls output power of the converter to the negative power reference over a constant power range between the output voltage reference and a maximum negative power limit, and a constant current module limits output current to a positive output current reference in a range between a minimum output voltage and output power of the converter reaching the positive power reference.

Abstract: An interface circuit for a telephone instrument forming part of a character display phone PBX system. The circuit is connected to receive data signals indicative of the condition of the character display and keyboard portions of the instrument, and to store and manage the incoming data and produce a serial RS232 output for communication of the data to a computer or terminal device. The interface enables the use of a computing device to store large amounts of information related to potential calling parties and called parties which may be identified in the display of the telephone instrument and also to associate such information with messages entered into the computer via the keyboard. The overall system thus enables custom answering of a multiplicity of lines of such a character display phone system and use of a single multi-line phone as a messaging center.

Abstract: A triac functions as an electronic switch to intermittently connect the AC power circuit to a load, and is directly connected to the output of a 1422 integrated circuit timer which turns the triac on and off according to a controlled cycle. The timer functions as an astable multivibrator which alternately produces high or low output voltages responsive to movement of a control voltage between high and low trigger voltage levels. A charging circuit, including a capacitor and variable resistor, is connected directly between the DC power supply and the timer input to produce an increasing control voltage; and the control voltage is discharged through the timer to produce a decreasing control voltage which determines the duty cycle. The duty cycle is variable by means of a variable resistor in the charging and discharge circuits; and the control includes calibration for the time base.

Abstract: This data transmitting apparatus is illustrated in a system for the remote reading of water meters. It includes a passive transmitter operated by the meter, a receiver including a source of energy, and means for connecting the receiver and its energy source to the transmitter. The receiver includes electrical loading means enabling it to read a submerged meter. The receiver is compatible with one type of transmitter having 14 output wires and with another type having only three. The data, e.g., a reading of a meter, is transmitted as binary data in a word of 16 characters, each comprising four bits. A pulse coding system is insensitive to noise, and includes a first bit detector for each character, and a final character detector for each word. The receiver detects open circuits in the transmitter and produces an error signal in response to such open circuits. The receiver and transmitter may be coupled through a manual connector.