摘要:
A resistance adjustable of resistance mirror circuit having a master resistor R0, a reference current source terminal providing a current value I0 through the master resistor R0 to ground; a first transistor; a current mirror source terminal providing a current value n I0, through the first transistor to ground; an operational amplifier having a positive terminal connecting to a drain of the first transistor, a negative terminal connecting to the other terminal of the master resistor R0, and an output terminal connecting to a gate of the first transistor; a mirror resistor set composed of a plurality of transistors in parallel each other and having their source electrode connecting to ground. Each transistor of the mirror resistor set has a ratio of channel width over channel length being m-fold of that of the first transistor, where m, n is any positive numbers. Since gates of the transistors connect to the output terminal of the operational amplifier, each of the transistors therefore has an equivalent resistance Req=(1/nm)R0.
摘要:
A programmable voltage supervisory circuit and method with minimum programming pins and low quiescent current is provided to monitor a supply voltage, by which only one programming pin can configure three voltage levels for the threshold voltage to be compared to the supply voltage. The programming pin is connected with a voltage select signal that is defined to be high, low or floating states each determines a setting voltage among three levels corresponding to the three threshold voltages, respectively, by a voltage select circuit. A sample/hold circuit in combination with a switch arrangement is further connected to the voltage select circuit such that the programmable voltage supervisory circuit is only operationable during the duty of a clock and thereby to reduce the power consumption thereof by squeezing the duty.
摘要:
In a synchronized data communication on a one-wired bus, it transmits and receives a synchronizing signal that segments part of or all proportions of the data signal by use of three electrically distinguishable statuses for the identifier of the synchronizing signal and the logic states of the data signal to increase the endurance of frequency displacement and resist influences of the interference of external conditions, low quality of transmission medium, and limitation of transmission distance and make the reliability and correctness of the signal transmission improve substantially. It is also clearly illustrated the feasibility and simplicity for implementing the one-wired synchronized communication by a plurality of exemplary signal types and a transceiver circuitry.
摘要:
An inductor equivalent circuit is disclosed. The circuit comprises a reference current source, a first current mirror, a second current mirror, two operational amplifiers OP1 and OP2, a capacitor, a first transistor, a second transistor, a mirror resistor set, and a bypass current source in parallel with the capacitor. An input signal is through OP1 and second transistor to control the reference current source. The first mirror current is then feed-back a signal to the first transistor through an OP2. The current signal makes the drain current of the first transistor lags the input voltage signal by 90° due to the capacitor coupled with the first mirror current source. The mirror resistor set can be resistors having one common terminal grounded, and other terminals each, respectively, coupled with the first and the second transistor and the capacitor, or can be composed of transistors and all of them with gate property biased so that the transistors in the mirror resistor set are operated in an ohmic region. The second mirror current provides an output current of the inductor equivalent circuit for next cascade stage.
摘要:
A linear voltage regulator comprises a transistor for converting a supply voltage to an output voltage. By directly monitoring the supply voltage and thereby rapidly responding when the supply voltage suffers a ripple, the linear voltage regulator enhances the stability of the output voltage.
摘要:
The present invention discloses a load-dependent frequency jittering circuit, comprising: a load condition detection circuit for receiving a switching signal and generating an output according to a load condition; a number generator for receiving the output of the load condition detection circuit and generating a number; a digital to analog converter for converting the output of the number generator to an analog signal; and an oscillator for generating a jittered frequency according to the output of the digital to analog converter.
摘要:
A frequency jittering control circuit wherein by means of the characteristics of a PLL whose input switches between different frequencies, the output frequency of the PLL swings between the different frequencies to achieve the desired frequency jittering.
摘要:
For protecting a power system, two or three of over current, thermal and under voltage protection circuits are integrated as one protection circuit but operate independently, and one or more protection points thereof are adjusted dynamically in response to detected condition of the power system. Specifically, using voltage and current conditions in the power system to modify the over current protection and the thermal protection maximizes the performance of the power system and covers the process bias in the circuits.
摘要:
The present invention discloses a half-voltage headphone driver circuit, comprising: at least one operational amplifier providing an output to a headphone speaker, and a charge pump receiving a supply voltage (VDD), generating a positive half-voltage and a negative half-voltage (VDD/2 and −VDD/2) based on the supply voltage, and supplying the positive half-voltage and negative half-voltage as high and low operation levels to the at least one operational amplifier.
摘要:
The present invention discloses a half-voltage headphone driver circuit, comprising: at least one operational amplifier providing an output to a headphone speaker, and a charge pump receiving a supply voltage (VDD), generating a positive half-voltage and a negative half-voltage (VDD/2 and −VDD/2) based on the supply voltage, and supplying the positive half-voltage and negative half-voltage as high and low operation levels to the at least one operational amplifier.