摘要:
Switchable voltage level supplies for circuitry in a multi-mode communications chipset are disclosed. In an embodiment, a first voltage level is supplied to TX circuitry operating in a first mode having a first set of linearity and/or noise requirements. A second voltage level lower than the first voltage level is supplied to TX circuitry operating in a second mode having a second set of linearity and/or noise requirements looser than the first set of requirements. The first mode may be operation according to the GSM standard, and the second mode may be operation according to the W-CDMA standard.
摘要:
A cascode amplifier with protection circuitry is described. In one exemplary design, the amplifier includes multiple branches coupled in parallel, with at least one branch being switchable between “on” and “off” states. Each switchable branch includes a gain transistor coupled to a cascode transistor. The gain transistor amplifies an input signal and provides an amplified signal in the on state and does not amplify the input signal in the off state. The cascode transistor buffers the amplified signal and provides an output signal in the on state. The output signal swing may be split between the gain transistor and the cascode transistor in both the on and off states with the protection circuitry. Each transistor may then observe a fraction of the voltage swing. The voltage splitting in the off state may be achieved by floating the gain transistor and shorting the gate and source of the cascode transistor.
摘要:
Techniques for protecting a power amplifier (PA) are described. In an exemplary design, an apparatus includes (i) a PA module to amplify an input RF signal and provide an output RF signal and (ii) a protection circuit to control a transmitter gain to protect the PA module against high peak voltage. In an exemplary design, the protection circuit includes a set of comparators to quantize an analog input signal and provide digital comparator output signals used to adjust the transmitter gain. In another exemplary design, the protection circuit reduces and increases the transmitter gain with hysteresis. In yet another exemplary design, the protection circuit has faster response to rising amplitude than falling amplitude of the output RF signal. The hysteresis and/or the different rise and fall responses may allow the protection circuit to avoid toggling the transmitter gain under severe load mismatch and to handle time-varying envelope due to amplitude modulation.
摘要:
A multi-mode multi-band power amplifier (PA) module is described. In an exemplary design, the PA module includes multiple power amplifiers, multiple matching circuits, and a set of switches. Each power amplifier provides power amplification for its input signal when selected. Each matching circuit provides impedance matching and filtering for its power amplifier and provides a respective output signal. The switches configure the power amplifiers to support multiple modes, with each mode being for a particular radio technology. Each power amplifier supports at least two modes. The PA module may further include a driver amplifier and an additional matching circuit. The driver amplifier amplifies an input signal and provides an amplified signal to the power amplifiers. The additional matching circuit combines the outputs of other matching circuits and provides an output signal with higher output power. The driver amplifier and the power amplifiers can support multiple output power levels.
摘要:
A high linear fast peak detector having a variable bias current and/or a variable bias voltage is described. In an exemplary design, the peak detector includes a transistor, a variable current source, a capacitor, and a feedback circuit. The transistor receives the input signal and provides a source current. The variable current source receives the input signal, provides high bias current when the input signal is low, and provides low bias current when the input signal is high. The capacitor is charged by the source current when the input signal is high and is discharged by the high bias current when the input signal is low. The feedback circuit receives a detected signal from the capacitor and provides higher bias voltage for the transistor when the input signal is high, which results in higher source current from the transistor.
摘要:
A device with multiple multi-mode low-noise amplifiers (LNAs), each with common operating modes and separate operating frequency bands, are coupled to shared degenerative inductors for common operating modes. Common load inductors are coupled to the multi-mode LNA outputs to reduce the number of load inductors required. The multi-mode LNAs have parallel transistor gain stages and form part of an integrated circuit (IC) for use in a wireless communication receiver. Each multi-mode LNA has the capability to switch between at least one higher linearity transistor gain stage and at least one lower linearity transistor gain stage for different operating modes. Multiple lower linearity transistor gain stages for different multi-mode LNAs may be merged into a single lower linearity transistor gain stage shared among multiple multi-mode LNAs through multiple RF switches between a set of common RF inputs and common inputs and common input matching networks.
摘要:
Exemplary embodiments of the disclosure are directed to down-converting an RF signal of a transmitter to baseband, filtering the down-converted signal, and generating a composite signal based on the filtered down-converted signal and a transmission based-band signal.
摘要:
A high linear fast peak detector having a variable bias current and/or a variable bias voltage is described. In an exemplary design, the peak detector includes a transistor, a variable current source, a capacitor, and a feedback circuit. The transistor receives the input signal and provides a source current. The variable current source receives the input signal, provides high bias current when the input signal is low, and provides low bias current when the input signal is high. The capacitor is charged by the source current when the input signal is high and is discharged by the high bias current when the input signal is low. The feedback circuit receives a detected signal from the capacitor and provides higher bias voltage for the transistor when the input signal is high, which results in higher source current from the transistor.
摘要:
Switches with connected bulk for improved switching performance and bias resistors for even voltage distribution to improve reliability are described. In an exemplary design, a switch may include a plurality of transistors coupled in a stack and at least one resistor coupled to at least one intermediate node in the stack. The transistors may have (i) a first voltage applied to a first transistor in the stack and (ii) a second voltage that is lower than the first voltage applied to bulk nodes of the transistors. The resistor(s) may maintain matching bias conditions for the transistors when they are turned off. In one exemplary design, one resistor may be coupled between the source and drain of each transistor. In another exemplary design, one resistor may be coupled between each intermediate node and the first voltage. The resistor(s) may maintain the source of each transistor at the first voltage.
摘要:
A device with multiple multi-mode low-noise amplifiers (LNAs), each with common operating modes and separate operating frequency bands, are coupled to shared degenerative inductors for common operating modes. Common load inductors are coupled to the multi-mode LNA outputs to reduce the number of load inductors required. The multi-mode LNAs have parallel transistor gain stages and form part of an integrated circuit (IC) for use in a wireless communication receiver. Each multi-mode LNA has the capability to switch between at least one higher linearity transistor gain stage and at least one lower linearity transistor gain stage for different operating modes. Multiple lower linearity transistor gain stages for different multi-mode LNAs may be merged into a single lower linearity transistor gain stage shared among multiple multi-mode LNAs through multiple RF switches between a set of common RF inputs and common inputs and common input matching networks.