Abstract: A battery power conversion circuit comprising a cell equalization circuit that ensures that each cell in a multiple battery cell stack is depleted of charge at an equal rate. The stack is coupled to provide current to a primary winding of a transformer. Each of the nodes between cells is coupled to the primary winding of the transformer through a transistor such that an equal number of turns of the primary winding are present between each node. An additional transistor coupled in series with the primary winding controls the current through the primary winding such that a capacitor coupled to a secondary winding of the transformer may be charged by an induced secondary current to a desired voltage level for powering a load. A controller circuit monitors the output voltage level and controls the transistor in series with the primary winding for maintaining the desired load voltage through a feedback loop.

Abstract: A circuit for supplying power to a fluorescent lamp comprising a buck regulator with a high side drive. A dc battery is coupled to a drain of a first transistor. A source of the first transistor is coupled to an inverter for powering the lamp. A first control signal is coupled to a primary winding of a transformer. A first terminal of a secondary winding of the transformer is coupled to the anode of a diode. The cathode of the diode is coupled to the gate of the first transistor. A second terminal of the secondary winding of the transformer is coupled to the source of first transistor. The first control signal is activated to bias the first transistor through the transformer by charging the gate to a voltage higher than the control voltage due to the transformer turns ratio. A diode is coupled to capture a charge on the gate. A second transistor is coupled to the gate of the first transistor to drain the captured charge to ground, turning off the first transistor when a second control signal is activated.

Abstract: A circuit for sensing a current in a fluorescent lamp. A control system comprises a buck regulator circuit for supplying a buck current, an inverter circuit for receiving the buck current and for generating a lamp voltage, a circuit for sensing a current in a fluorescent lamp, and a controller for controlling the buck regulator and the inverter. The inverter comprises a Royer-type inverter, a resonant tank, and a transformer. A current flows through a primary winding of the transformer to generate a voltage in a secondary winding of the transformer. The fluorescent lamp is coupled to the secondary winding of the transformer so that the fluorescent lamp is isolated from the remainder of the control system by the transformer. The circuit for sensing the current in the lamp senses a current in the Royer-type inverter which is representative of the current in the lamp. The circuit for sensing the current in the lamp is coupled to the controller for controlling the buck regulator and the inverter.

Abstract: A circuit for supplying power to a fluorescent lamp. A control system comprises a buck regulator for supplying a buck current, an inverter circuit for receiving the buck current and for generating a lamp voltage, a circuit for sensing a current in a fluorescent lamp, a circuit for sensing a no lamp condition, and a controller for controlling the buck regulator and the inverter. The circuit for sensing a no lamp condition monitors a voltage level at the inverter transformer. The controller is coupled to the circuit for sensing a no lamp condition. If a no lamp condition is detected, the controller responds by shutting itself down. The controller can be reactivated by toggling an on/off signal to reset a latch.

Abstract: The present invention is for an architecture for an input circuit to a linear circuit having a circuit ground from a linear system having a system ground. The architecture has a linear input signal which is coupled into a current limiting input impedance. The current limiting input impedance is not connected to the system ground. A linear input circuit is coupled to receive the reduced input signal and is coupled to the circuit ground. Accordingly, the analog input to the linear input circuit is a current signal rather than a voltage signal.

Abstract: A low dropout voltage regulator with a switched redundant input, which has low dropout voltage before, during, and after a switch to the redundant input. In a preferred embodiment, the inventive voltage regulator includes two transistors that are controlled by the output of an error amplifier, and redundant input voltage sources. A first one of the transistors conducts when a first input voltage is greater than a second input voltage. The other transistor conducts when the second input voltage exceeds the first input voltage. When both input voltages are have substantially equal magnitude, both transistors conduct. In a preferred embodiment, one input voltage is supplied by a battery, and the other is supplied by a storage capacitor charged by the battery. When the battery fails, the storage capacitor will discharge, thus serving as a time-varying redundant voltage source in the event of battery failure.

Abstract: An over voltage detection circuit for utilization in conjunction with a series driver transistor type electronic ignition system which samples the voltage magnitude appearing at the collector of the series driver transistor to render the same nonconductive when a high voltage condition appears at the collector thereof. The over voltage detection circuit includes a voltage translation circuit for translating the level of the voltage appearing at the collector of the series driver transistor to a second level, and a sampling transistor the base of which is coupled to the voltage translation circuit and with the collector-emitter path coupled in series between the collector of the series driver transistor and an output of the detection circuit which is rendered conductive in response to the translated voltage exceeding a predetermined threshold level for supplying an output signal which is utilized to render the series driver transistor nonconductive.

Abstract: An interface circuit adapted to receive an analog input signal for generating first and second output signals at respective outputs in response to the input signal varying above a first reference voltage level and varying below a second reference voltage level. The interface circuit comprising first and second circuits each of which has an input coupled to the input of the interface circuit and receiving the first and second reference voltage levels respectively. Each one of the two circuits includes a voltage translation circuit for translating the reference voltage level supplied thereto and a comparator to produce the particular output signal in response to the input signal level assuming the aforementioned relationship with respect to the respective two reference voltage levels.

Abstract: An integrated circuit is operative to produce an output current to a load and for switching the output current when a predetermined peak magnitude of load current is reached to a lower predetermined constant value. The circuit includes an internal power stage rendered conductive for producing maximum load current through the external load which is connected in series therewith in response to an internally generated reference current. The power stage comprises a multi-emitter power transistor with each emitter coupled to a respective emitter ballast resistor such that the load current through one of the resistors may be sensed and compared to the reference current to cause the magnitude of this reference current to be switched from a maximum value to a minimum value when the sensed current is representative of the peak magnitude value of current to thereby reduce the load current until the magnitude thereof is representative of the lower level of reference current.

Abstract: A circuit suitable to be utilized in an electronic ignition system or the like which receives periodic signal information and which is caused to ignore this information during a portion of each period a predetermined time interval after initiation of each period. The circuit comprises a blanking circuit which is responsive to control signals generated from the input signal information at the predetermined time interval after initiation thereof to produce a blanking signal the duration of which last during the portion of the period and a coincidence gate that is inhibited by the blanking signal but enabled during the remaining portion of each period to pass the signal information between an input and output thereof.

Abstract: A circuit responsive to a supplied control input signal for alternately sourcing and sinking current at an output the values of which are accurately matched comprising a single current reference source and a single NPN current mirror circuit. The current reference source is unilaterally coupled to the output when the circuit is in a first mode of operation to provide the source current and is coupled to the NPN current mirror circuit which is rendered conductive in a second mode of operation to provide the input current to said current mirror. The output of the current mirror being coupled to the output sinks current thereat which is substantially equal to the input current supplied thereto. The NPN current mirrors comprises a pair of matched transistors having the bases and emitters interconnected at first and second nodes respectively.

Abstract: A three terminal current source is disclosed including a current turn around circuit comprising first and second transistors. The emitters of the pair of transistors are coupled to a common terminal with the collector of the first one of the pair of the transistors being coupled to an input terminal at which is supplied a reference current with the collector of the other one of the pair of transistors being coupled in cascode through the emitter collector path of an output transistor to the output terminal of the current source circuit. The base electrodes of the pair of transistors are directly connected to each other with the control electrode of the output transistor being connected to the collector of the first one of the pair of transistors of the current turn around circuit.