Capacitance Transient Spectroscopy

A power amplifier module comprises a plurality of amplifier stages, each including a reference amplifier for emulating the operation of the amplifier. The current flowing to the base of a bipolar transistor that forms each reference amplifier depending on an input power level is detected, amplified, and supplied as base current of the transistor of the corresponding amplifier.

Power amplifier module

Power reception circuits employable in portable data devices (e.g., smart cards) to derive power and/or data from an input AC power signal (e.g., an ASK modulated carrier signal). In one embodiment, the power reception circuit comprises a power rectifier (120), a shunt rectifier (142) and a shunting element (132). The power rectifier (120) is adapted to rectify the input power signal, yielding a rectified output waveform. The shunt rectifier (142) is connected in parallel with the power rectifier (120). The shunting element (132) is connected to the shunt rectifier (142) and is operable to regulate an output voltage or current waveform produced at the output of the power rectifier (120). In another embodiment, the power reception circuit includes an analog circuit (610) for recovering data from a modulated carrier signal. A decoupling device (630) isolates the analog circuit (610) from impedance variations of a load. A shunt device (640) diverts undesired current from the load.

Power reception circuits for a device receiving an AC power signal

A pair of protection circuits, each forming a silicon controlled rectifier (SCR) for protecting a circuit against either negative or positive voltage transients, are formed in a single isolated region together with a bond pad A second embodiment also includes a sense resistor in the isolated region

Protection circuit for integrated circuit devices

A monolithic microwave integrated circuit (MMIC) semiconductor chip, for use with a hybrid coupler, in a frequency downconverter. The chip has a first input lead for receiving a first combined input signal from the coupler, a second input lead for receiving a second combined input signal from the coupler, and an output lead. Each input signal is a microwave signal combined with a further frequency signal, and one of the microwave and further frequency signals of the first combined signal is out of phase with one of the microwave and further frequency signals of the second combined signal. A single balanced mixer has a first single ended mixer for converting the first combined signal to a first intermediate frequency signal and a second single ended mixer for converting the second combined signal to a second intermediate frequency signal. An amplifier is coupled to the first and second mixers for forming an amplified unbalanced intermediate frequency (IF) signal at the output lead representative of the first and second intermediate frequency signals.

Single balanced frequency downconverter for direct broadcast satellite transmissions and hybrid ring signal combiner

A temperature-independent reference voltage is developed as the difference between the offset potentials across first and second diode means, the second nested within the first to conduct the same forward bias current.

Reference voltage circuit using nested diode means

A first reference voltage which exhibits a negative coefficient of change with temperature is developed as an offset potential across a forward-biased semiconductor junction or a series string of such junctions operated at an absolute temperature T. A second reference voltage which varies in linear proportion to the absolute temperature T is additively combined with the first reference voltage to simulate a higher density of forward current flow through the semiconductor junctions.

Voltage reference circuits

PNP composite transistors connected as commonemitter amplifiers each comprise a PNP pre-amplifier transistor in direct coupled cascade with a plurality of parallelled NPN transistors. The emitter-electrode of the PNP transistor is connected to a sensing resistor in the collector path of one of these NPN transistors, causing the "base-to-emitter" potential of the composite transistor to increase if its "emitter" current exceeds a threshold current. By clamping this base-to-emitter potential if it exceeds a predetermined potential, the output current of the composite transistor is prevented from becoming excessive. This predetermined potential is controlled as a function of composite transistor temperature and supply potential to provide the required degree of over-current protection for these particular conditions.

Amplifier with over-current protection

An operational transconductance amplifier comprises first and second transistors connected in a gain-controlled emitter-coupled differential amplifier configuration and provided active collector loads by the input ports of a first and a second current mirror amplifiers, respectively. The balanced signals appearing at the output ports of the first and the second current mirror amplifiers in response to the balanced signal variations in the collector currents of the first and second transistors are converted to single-ended form by a third current mirror amplifier having its input and output ports connected to the output ports of the first and second current mirror amplifiers, respectively. Improved high-frequency operation of the gain controllable operational transconductance amplifier as an analog multiplier is obtained by applying common mode currents to the input ports of the first and second current mirror amplifiers. The responses to these common mode currents counteract and cancel each other in the output signal from the operation transconductance amplifier.

Operational transconductance amplifier

An improvement for lowering the source impedance exhibited by a shunt voltage regulator of the type including a self-biased transistor connected between the output terminals. A sensing resistance is connected between the base and collector of the self-biased transistor for providing a voltage responsive to the collector current that controls the conduction of current by a controllable current conductive device between the output terminals.

Jr. Carl Franklin Wheatley

Papers

Reference voltage circuit using nested diode means

Voltage reference circuits

Amplifier with over-current protection

Operational transconductance amplifier

Shunt voltage regulator