摘要:
A method and apparatus for providing a temperature sensing loop used in connection with a current sensing component, such as a BATFET, in order to compensate for variations in the BATFET's resistance due to temperature variations. The temperature sensing loop detects a temperature of the BATFET and regulates the gate voltage of the BATFET based on the detected temperature in order to compensate for changes in the BATFET's resistance. The temperature sensing feedback loop maintains the BATFET at a constant resistance for current sensing through negative feedback control. The BATFET and temperature sensing loop can be provided as components of an on-chip fuel gauging application for a UE.
摘要:
A method and apparatus for providing a temperature sensing loop used in connection with a current sensing component, such as a BATFET, in order to compensate for variations in the BATFET's resistance due to temperature variations. The temperature sensing loop detects a temperature of the BATFET and regulates the gate voltage of the BATFET based on the detected temperature in order to compensate for changes in the BATFET's resistance. The temperature sensing feedback loop maintains the BATFET at a constant resistance for current sensing through negative feedback control. The BATFET and temperature sensing loop can be provided as components of an on-chip fuel gauging application for a UE.
摘要:
A method and apparatus for derating current and for derating current for a camera flash. The method comprises monitoring a local junction temperature of a module. The local junction temperature is converted into a local junction current. The local junction current is then compared with a reference current, which is independent of temperature. After the current comparison and subtraction is made, a derate control current is obtained to generate the LED reference current. After the temperature crosses the temperature threshold, the derate control current is derated. Both the temperature threshold and current derate slope are programmable and precisely controlled. The LED output current is regulated and proportional to the LED reference current. If the local junction temperature is greater than the temperature threshold, the LED output current is derated at the moment of the camera flash to avoid thermal overload.
摘要:
Methods and apparatus for a switchable balun for combined BLUETOOTH® and WLAN operation. A switchable balun is provided that includes an input circuit for receiving an amplified signal, the input circuit comprising first and second coils connected at a center tap, an output circuit comprising a third coil that is inductively coupled to the first and second coils, the output circuit for outputting an adjusted version of the amplified signal for transmission in a selected transmission mode, and a switch coupled to the center tap, wherein the switch is configured to couple a first voltage to the center tap to select operation in a first transmission mode and to couple a second voltage to the center tap to select operation in a second transmission mode.
摘要:
A system and method for detecting and correcting excess current in a power amplifier in a transmit chain of a mobile terminal are provided. Over current detection and correction circuitry compares a current detection signal indicative of an output current of the power amplifier to a maximum current ramp during ramp-up for a transmit burst. If the current detection signal exceeds the maximum current ramp, then a power control signal controlling a supply voltage provided to the power amplifier circuitry is reduced, thereby reducing the output power and output current. Over voltage detection and correction circuitry compares a voltage detection signal indicative of an output voltage of the power amplifier to a maximum voltage ramp during ramp-up for the transmit burst. If the voltage detection signal exceeds the maximum voltage ramp, then the power control signal is reduced.
摘要:
A system is provided for correcting an output power of a power amplifier in a transmit chain of a mobile terminal. In one embodiment, the system includes output power correction circuitry that corrects the output power of the power amplifier during ramp-up for a transmit burst. The output power of the power amplifier is controlled based on a power control signal, which is provided by combining an amplitude component of a modulated signal and a corrected ramping signal provided by the output power correction circuitry. In general, a power amplifier ramp generator provides a ramping signal. The ramping signal is converted to a desired output power signal, which is subtracted from a detected output power signal to provide an error signal. The error signal is integrated to provide an adjustment signal, which is combined with an ideal ramping signal to provide the corrected ramping signal.
摘要:
A method for self testing a multiband voltage controlled oscillator (VCO) is described. A first frequency band in a VCO is selected. An N value is selected for a frequency divider that produces a tuning voltage for the VCO that is between a low tuning voltage limit and a high tuning voltage limit for the VCO. The N value is adjusted in one direction until the tuning voltage reaches one of the tuning voltage limits. This N value at the tuning voltage is a first limit value. The frequency bands are switched from the first frequency band to a second frequency band that is adjacent to the first frequency band.
摘要:
A method for self testing a multiband voltage controlled oscillator (VCO) is described. A first frequency band in a VCO is selected. An N value is selected for a frequency divider that produces a tuning voltage for the VCO that is between a low tuning voltage limit and a high tuning voltage limit for the VCO. The N value is adjusted in one direction until the tuning voltage reaches one of the tuning voltage limits. This N value at the tuning voltage is a first limit value. The frequency bands are switched from the first frequency band to a second frequency band that is adjacent to the first frequency band.
摘要:
Systems and methodologies are described that facilitate calibration of the loop bandwidth of a phase-locked loop (PLL). Calibration for the loop bandwidth of a PLL as described herein can be performed by optimizing the loop response of the PLL. Optimization of the loop response of the PLL can be achieved by modifying the value of a feedback counter of the PLL to induce a loop response at the PLL. The loop response of the PLL can be measured and compared to an ideal loop response. Based on this comparison, appropriate adjustments can be made to the PLL. Further, various techniques described herein facilitate calibration of a PLL by adjusting only parameters of a charge pump of the PLL without requiring individual control mechanisms for each element of the PLL, thereby improving PLL performance and manufacturing yield.
摘要:
A method and apparatus for derating current and for derating current for a camera flash. The method comprises monitoring a local junction temperature of a module. The local junction temperature is converted into a local junction current. The local junction current is then compared with a reference current, which is independent of temperature. After the current comparison and subtraction is made, a derate control current is obtained to generate the LED reference current. After the temperature crosses the temperature threshold, the derate control current is derated. Both the temperature threshold and current derate slope are programmable and precisely controlled. The LED output current is regulated and proportional to the LED reference current. If the local junction temperature is greater than the temperature threshold, the LED output current is derated at the moment of the camera flash to avoid thermal overload.