Abstract: A power amplifier configuration including power amplifier circuitry and power control circuitry and having improved Power Added Efficiency (PAE) is provided. The power amplifier circuitry includes one or more input amplifier stages in series with a final amplifier stage. The power control circuitry provides a variable supply voltage to the input amplifier stages based on an adjustable power control signal. The final amplifier stage is powered by a fixed supply voltage. In operation, as output power of the power amplifier is reduced from its highest power level, the variable supply voltage is reduced. Accordingly, RF power of an amplified signal provided to the final amplifier stage from the input amplifier stages decreases, and the final amplifier stage transitions from saturation to linear operation, thereby increasing the gain of the final amplifier stage. Thus, a desired output level can be maintained while operating at lower current levels.

Abstract: A battery powered radio device includes a transmitter, a control circuit, and a lockout circuit. The transmitter transmits radio communications and the transmitter includes a power amplifier which generates an amplified radiofrequency output signal. More particularly, the power amplifier uses both a positive supply voltage and a negative bias voltage for operation wherein the negative bias voltage is less than a supply ground voltage. The control circuit enables the power amplifier during transmission, and the control circuit includes a switch coupled in series between a positive supply voltage and the power amplifier. The switch is activated in response to a transmit activation signal when the negative bias voltage is coupled to the power amplifier. The lockout circuit prevents activation of the switch in response to the transmit activation signal when the negative bias voltage is not coupled to the power amplifier.

Abstract: An electromechanical circuit uses a plunger to open and close a circuit as an indication of the position of a flip portion of a mobile communication device. The plunger includes an electrically conductive portion which slidingly contacts a contact pad. Upon contacting the contact pad, a change in logic states occurs which triggers circuitry to activate or de-activate the internal electronics within the communication device. This allows a user, for example, to activate a phone to receive a call without having to depress a specified switch. A common cam-follower mechanical configuration is used to cause the plunger to translate axially as the flip portion is moved.