Sipex Corporation

Raymond W Chow

Paul S Chan

Henry K Wong

Joost Decupere

Kim Lee

Circuit and method for determining the presence of a load in a circuit including on a charge pump. The circuit monitors the state of a pump signal indicative of the operating status of the charge pump. The circuit generates a signal indicating the presence or absence of a load. The signal is used to deactivate features of an associated device, thereby reducing the power consumption and extending the life of the power supply (e.g., battery) for the device.

Charge pump load determination circuit

A circuit and a method are presented which allow for the detection of an active communication device connected to the circuit. The circuit output signal can be used to reduce the power consumption of related equipment when communication is not detected for a predetermined period of time. The circuit includes a plurality of input terminals coupled to respective inactive detection blocks. The circuit also includes an accumulated delay block having delay circuits in serial electrical communication. Each inactive detection block provides a signal to a respective delay circuit that indicates whether the corresponding input terminal is connected to an active driver in the communication device. Each delay circuit provides a delayed output signal to a subsequent delay circuit. The accumulated delay block provides an output signal indicating the presence or absence of the communication device based on the activity at the input terminals over the predetermined period of time.

Connection detection circuit and method

A V.35 compliant driver is disclosed. The driver has three operational modes: OFF, low power (approximately 1/3 full power), and full power. The driver is placed in an appropriate mode based on conditions sensed at driver outputs. More particularly, the driver turns OFF upon sensing a short circuit condition, and reverts back to a normal operating condition following cessation of the short circuit condition by transitioning through a low power mode. Innovative approaches for satisfying V.35 source impedance measurement requirements and driver termination are also disclosed. All of the components associated with the driver reside on a single integrated circuit.

V.35 network terminator

A programmable charge pump produces a selected one of a plurality of bipolar output voltages in response to a pump select input signal. Transistor switches in the charge pump are controlled by logic circuitry so as to provide the selected bipolar output voltages. The charge pump may include a power management circuit to optimize power consumption by varying the clock frequency based on the current being drawn by the load. The charge pump may be fabricated as an integrated circuit which supports a plurality of interface standards requiring different bipolar supply voltages.

Programmable charge pump

A voltage tripler which uses a charge pump with a single charge transfer capacitor to produce the required voltage is disclosed. The voltage tripler in conjunction with an inverter is useful for producing voltages with negative polarities. The voltage tripler when used in conjunction with a variable frequency oscillator circuit is useful in optimizing the power consumption by the charge pump of the voltage tripler when the tripler is not operating under load conditions. The tripler is useful in supplying power to a combination RS232 and RS422 or RS232 and RS485 interface, as well as other monolithic interface products.

Voltage tripler using a charge pump having a single multiplexed charge

Charge pump circuitry is implemented using a voltage shifting technique to generate a symmetrical bipolar voltage. The symmetrical bipolar voltage charge pump power supply can be fabricated as an integrated circuit on a single substrate, and can be integrated with various interface circuits to provide symmetrical bipolar voltage thereto. The charge pump includes voltage shifting circuitry which generates an increased output voltage of a negative polarity and an increased output voltage of a positive polarity. The shifting circuitry is responsive to an internal oscillator which triggers charge accumulation and voltage shifting. Neither output voltage is generated from the other output voltage. Rather, the negative and positive supply voltages are each generated, in substantially the same manner, by charge transfer effected by the voltage shifting circuitry in response to triggering by the internal oscillator. Additional circuitry can be fabricated on a single substrate in combination with the presently disclosed charge pump to effect the optimum utilization of circuit board area while minimizing power consumption.

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Saratoga, CA, United States of America

Raymond W Chow