摘要:
A linear type of voltage regulator, having at least one input terminal adapted to receive a supply voltage and one output terminal adapted to deliver a regulated output voltage, includes a power transistor and a driver circuit for the transistor. The driver circuit includes an operational amplifier having an input differential stage biased by a bias current which varies proportionally with the variations of the regulated output voltage at the output terminal of the regulator.
摘要:
A control circuit for controlling current of batteries at the end of the charging phase, especially for lithium batteries, including an input/output circuit, placed between a battery charger and a battery, and an output stage, including two transistors, wherein the resistance of one of the two transistors is modulated to increase the value of the total resistance and to cause a lower turning off current of said output stage.
摘要:
An integrated circuit voltage ramp generator is presented. The circuit includes at least one operational amplifier having a non-inverting input terminal connected to a voltage reference, and having an output terminal coupled in a feedback relationship to an output terminal of the generator circuit. The ramp voltage generator further includes a first storage capacitance connected between the non-inverting input terminal of the operational amplifier and a ground reference, which is loaded by means of a second pumping capacitance connected in parallel to the first capacitance. The pumping and voltage generation is and controlled by a series of passgates coupled to clock signals.
摘要:
A battery-charging electronic device comprises a current generator adapted to supply a charging current to a battery and a controlled current edge switch having a circuit for controlling the switching edges of current being flowed through a power transistor. The switching edge control circuit comprises a controlled edge variable voltage generator for generating a controlled edge voltage signal, a voltage/current converter for converting the voltage signal to a controlled edge current signal, and a driver circuit for the power transistor being input the controlled edge current signal to mirror, onto the power transistor, an output current which is proportional to the controlled edge current signal.
摘要:
A linear type of voltage regulator, having an input terminal adapted to receive a supply voltage thereon, and an output terminal adapted to deliver a regulated output voltage, includes a power transistor and a driving circuit therefor. The driving circuit includes an operational amplifier having a differential input stage biased by a bias current which varies proportionally with the output current of the regulator.
摘要:
A voltage multiplier includes a control circuit that generates first and second signals in phase opposition and a charging section. The latter comprises a first capacitor having a first terminal coupled to the first signal and a second capacitor having a first terminal coupled with the second signal. The multiplier includes respective parasitic capacitances placed respectively between the capacitors and a reference voltage. The charging section is coupled with an input voltage and is suitable for producing an output voltage that is a multiple of the constant voltage. The multiplier comprises a switch that selectively connects the parasitic capacitances to carry out a charge transfer from one parasitic capacitance to the other.
摘要:
A system for driving columns of a liquid crystal display includes logic circuitry operating in a supply path between a first and a second supply voltage in which the first supply voltage is higher than the second supply voltage. The logic circuitry is capable of generating first logic signals and second logic signals whose value is equal to the first or second supply voltage. The system includes two level shifters coupled to the logic circuitry and operating in a supply path between a third supply voltage greater than the first supply voltage and the second supply voltage; the level shifters are capable of raising the value of the second logic signals. The system also includes a first and a second pair of transistors having different supply paths and having an output terminal in common; the first and the second pair of transistors are coupled to the level shifters to determine the drive signal of a column. The system includes turnoff circuitry operating in a supply path between the third and the second supply voltage and coupled to the two level shifters. The turnoff circuitry is capable of keeping one of the two pairs of transistors in a turnoff state in the period of time of a frame when the other of the two pairs of transistors is operative.
摘要:
A non-dissipative device for protecting an integrated circuit having multiple independent channels against overloading. The non-dissipative device includes an input terminal and an output terminal having an integrated switch connected therebetween which consists of an input portion, a logic gate with two inputs a control portion, and an output portion, all connected in series with one another. The device further includes a generating circuit for generating the on-times and off-times of the integrated switch, the generating circuit is connected between an output of the output portion and an input of the logic gate.
摘要:
Power consumption by the driving circuitry of an output stage, employing a slew-rate controlling operational amplifier, is reduced by modulating the level of the current output by the operational amplifier in function of the working conditions of the output stage. Switching delay may also be effectively reduced. An auxiliary current generator forces an additional current through the conducting one of the pair of input transistors of the operational amplifier only during initial and final phases of a transition, essentially when the slew rate control loop ceases to be effective. The boosting of the bias current through the conducting input transistor is determined by the degree of unbalance of the differential input stage of the operational amplifier, without the use of dissipative sensing elements.
摘要:
A method of power point tracking for operating a photovoltaic power plant, which includes a DC-DC converter of the output voltage of a panel having a power switch driven by a PWM control signal of variable duty-cycle generated by a PWM control circuit, in discontinuous conduction mode or continuous conduction mode depending on the current load of the converter, is implemented by low cost analog circuits. The method does not require the use of any analog-to-digital conversion, digital processing or storage resources and may use a single voltage sensor.