摘要:
An over-current detection circuit using the ON-voltage of a main MOSFET is provided, which is resistant to process variations of a main MOSFET and is not easily influenced by switching noise. Separately from a main MOSFET (Q1), a sense MOSFET (Q3) whose size is 1/m of the main MOSFET is provided and it is caused to be normally on. A DC ON-voltage generated when a current that is 1/m of an over-current value is caused to flow through the sense MOSFET is obtained as a reference voltage for over-current setting. The ON-voltage when the main MOSFET is on is sampled and held, and it is obtained as a DC voltage. These DC voltages are compared in a comparator (COMP).
摘要:
An over-current detection circuit using the ON-voltage of a main MOSFET is provided, which is resistant to process variations of a main MOSFET and is not easily influenced by switching noise. Separately from a main MOSFET (Q1), a sense MOSFET (Q3) whose size is 1/m of the main MOSFET is provided and it is caused to be normally on. A DC ON-voltage generated when a current that is 1/m of an over-current value is caused to flow through the sense MOSFET is obtained as a reference voltage for over-current setting. The ON-voltage when the main MOSFET is on is sampled and held, and it is obtained as a DC voltage. These DC voltages are compared in a comparator (COMP).
摘要:
An electric current flowing to an upper side power MOSFET during soft-start is detected according to an on-voltage of the MOSFET and an on-pulse width of a PWM pulse for driving the upper side power MOSFET is forced to be reset in the idle and decided according to a signal generated when the voltage falls below a predetermined specified voltage.
摘要:
A power-supply device comprising such marginal check voltage setting circuit that is easily adaptable to downsizing of the device and to configuration using ICs. The power-supply device of this invention comprises a marginal check voltage setting circuit that accepts input of a reference voltage and sets a desired marginal check voltage, an error amplifier that accepts input of the marginal check voltage and also the output voltage of the power-supply device and delivers output of an error signal, that is, the difference between the two inputs, a pulse width modulation oscillator that modulates the pulse width of the output from the error amplifier, a driver circuit that generates driving signal from the pulse signal originating from the pulse width modulation oscillator, and a pair of power semiconductor switching devices that work to step down the input voltage and generate an output voltage based on the driving signal. Furthermore, the power-supply device is also provided with an over-voltage detection circuit that sets an over-voltage detection reference voltage, and a power-good circuit that sets a power-good determination reference voltage, both circuits being positioned at the output terminal of the marginal check voltage setting circuit.
摘要:
A power-supply device including a marginal check voltage setting circuit that is easily adaptable to downsizing of the device and to configuration using ICs. The power-supply device of this invention includes a marginal check voltage setting circuit that sets a desired marginal check voltage, an error amplifier that delivers output of an error signal, a pulse width modulation oscillator that modulates the pulse width of the output from the error amplifier, a driver circuit that generates driving signal from the pulse signal originating from the pulse width modulation oscillator, and a pair of power semiconductor switching devices that work to step down the input voltage and generate an output voltage based on the driving signal. Furthermore, the power-supply device is also provided with an over-voltage detection circuit and a power-good circuit both circuits being positioned at the output terminal of the marginal check voltage setting circuit.
摘要:
A phase locked loop (PLL) circuit is provided to operate in a broad band, including two separate loops one of which is for feed-back of an output from an oscillator to the same oscillator through its associative proportional control unit and the other of which is for feed-back of an output of an oscillator to the same oscillator via an integral control unit. The proportional control unit is arranged to control an output frequency of the oscillator and is operable to generate a control signal based on a difference between input and output signals. The integral control unit is arranged to control the phase of an output signal of the oscillator to thereby generate a control signal based on a phase difference between input and output signals.
摘要:
A semiconductor device capable of achieving downsizing without reducing the power supply efficiency and capable of reducing switching noises and a memory card using the same are disclosed. The device comprises a plurality of stages of voltage booster circuits for potentially raising a power supply voltage up to a final output voltage, a voltage control unit for controlling an output voltage at a nearby location of the final stage, and one or more internal elements to which the final output voltage is supplied. A primary voltage booster circuit at the first stage includes an inductance element, a switching element, a diode and a driver circuit. At a metal core part of the inductance element, a metal wiring line is used, which was formed by use of a fabrication process of semiconductor integrated circuits, while employing for its core part an inter-wiring layer dielectric film that was formed using the fabrication process. In addition, the switching element and the diode are arranged so that portions thereof are disposed beneath the inductance element.
摘要:
A step-down type DC-DC power supply device implements both the stabilization of the control loop and the responsibility at the same time. In the power-supply device, an output power signal is fed back to an error amplifier after having passed through a CR smoothing filter provided independently of a power LC smoothing filter. Also, independently of the duty controls over Power MOSFETs, i.e., upper-side/lower-side semiconductor switching components in the steady state, an output from the power LC smoothing filter is added to an upper and lower limit-mode-equipped control circuit, thereby, at the transient state, forcefully setting the duty α at either 0% or 100%.
摘要:
A step-down type DC—DC power-supply device implements both the stabilization of the control loop and the responsibility at the same time. In the power-supply device, an output power signal is fed back to an error amplifier after having passed through a CR smoothing filter provided independently of a power LC smoothing filter. Also, independently of the duty controls over Power MOSFETs, i.e., upper-side/lower-side semiconductor switching components in the steady state, an output from the power LC smoothing filter is added to an upper and lower limit-mode-equipped control circuit, thereby, at the transient state, forcefully setting the duty &agr; at either 0% or 100%.
摘要:
A power-supply unit including a transformer, a full bridge circuit having four arm switches on a primary side of the transformer, a rectifier and smoothing circuit including two synchronous rectifier switches on a secondary side of the transformer, a choke coil, and a capacitor, an output terminal in the rectifier and smoothing circuit, a control circuit controlling ON/OFF of the four arm switches of the full bridge circuit and the two synchronous rectifier switches of the rectifier and smoothing circuit, a resonant inductor including a leakage inductor component and a parasitic inductor component on the primary side of the transformer, and a resonant capacitor, and in which the control circuit includes a timing variable unit which varies switching timings of the two synchronous rectifier switches of the rectifier and smoothing circuit based on an output current flowing in the output terminal provided in the rectifier and smoothing circuit.