摘要:
For a system to avoid abnormal operation caused by a shorted parameter setting pin of an integrated circuit, a protection apparatus and method apply a buffered reference voltage to the parameter setting pin to define an internal parameter of the integrated circuit by the buffered reference voltage and an external element connected to the parameter setting pin, and detect the rapid variation of the internal parameter to trigger a shutdown signal or slow down the speed of the variation of the internal parameter reflected to an adjustable signal of the integrated circuit.
摘要:
A multi-channel regulator system includes serially connected PWM integrated circuits, each of which determines a PWM signal for a respective channel to operate therewith, and individually controls its operation mode according to whether or not an external clock is detected. Therefore, each channel will not be limited to operate under a constant mode and could become a master channel or a slave channel. Additionally, each of the PWM integrated circuits generates a phase shifted synchronous clock for its next channel during it is enabled, and thus all the channels operate in a synchronous but phase interleaving manner.
摘要:
A feedback loop is used to optimize a zero current threshold for a switching regulator. After the low side power switch of the switching regulator turns off, the switching node state is monitored to adjust the zero current threshold in a real time and thus the low-side power switch is prevented from turning off too early or too late. Thereby the efficiency in green mode is optimized.
摘要:
A power off delay circuit includes a switch connected between an external power input terminal and an internal power supply terminal, a capacitor connected to the internal power supply terminal, and a hysteresis comparator to switch the switch according to the voltages of the external power input terminal and the internal power supply terminal. During on-time of the switch, the external power input terminal is connected to the internal power supply terminal and the capacitor can be charged by the external power source. When the switch is off, the capacitor provides electric power for an internal circuit. Application of the power off delay circuit to an audio system may eliminate the turn-off pops of the audio system.
摘要:
A power off delay circuit includes a switch connected between an external power input terminal and an internal power supply terminal, a capacitor connected to the internal power supply terminal, and a hysteresis comparator to switch the switch according to the voltages of the external power input terminal and the internal power supply terminal. During on-time of the switch, the external power input terminal is connected to the internal power supply terminal and the capacitor can be charged by the external power source. When the switch is off, the capacitor provides electric power for an internal circuit. Application of the power off delay circuit to an audio system may eliminate the turn-off pops of the audio system.
摘要:
An apparatus for interleaved phase shift clock synchronization includes a master clock generator and at least one slave clock generator. The master clock generator provides a ramp signal or reset signal for each slave clock generator to generate a clock synchronized with the clock of the master clock generator, and the master and slave clock generators have different reference voltages for generating clocks. Therefore, the clocks generated will be synchronized and interleaved phase with each other.
摘要:
A constant frequency ON-time control system applied to a voltage regulator is disclosed. The voltage regulator determines a time length of an input voltage inputted thereto according to an ON-time and thereby regulates an output voltage. The constant frequency ON-time control system includes a constant frequency ON-time control circuit for computing the ON-time according to a system duty cycle of the voltage regulator and a frequency setting parameter and a frequency setting parameter adjusting circuit for generating a frequency setting parameter adjust value according to an OFF-time corresponding to the ON-time and taking a result of operation between the frequency setting parameter adjust value and a preset frequency setting parameter as the frequency setting parameter. The frequency setting parameter adjusting circuit uses the frequency setting parameter adjust value to change the result of operation for varying the frequency setting parameter when the OFF-time is shorter than a reference value.
摘要:
A hysteretic mode LED driver for providing a driving current for an LED includes a hysteretic comparing circuit and a feedback loop. The hysteretic comparing circuit compares a driving current related sensing signal with a reference signal to control the average value of the driving current. The feedback loop senses the error between the average value of the driving current and a target value to adjust the reference signal or the offset of the hysteretic comparing circuit to adjust the average value of the driving current.
摘要:
A control circuit and method of a switching DC-DC power supply detects the error between the output voltage of the power supply and a design value of the output voltage and according to the error, determines an offset adjust signal to adjust the offset of an error comparator of the power supply to pull the output voltage toward the design value.