Fuji Electric Co., Ltd.

Fuji Electric Systems Co. Ltd.

Tetsuya Kawashima

Masahiro Sasaki

Akira Yamazaki

Satoshi Sugahara

Kouhei Yamada

Wai Tung Ng

Jing Wang

Haruhiko Nishio

Kendy Ng

A semiconductor device includes an internal power supply generation circuit that generates an internal power supply voltage from an external power supply voltage and a non-volatile memory circuit. The semiconductor device sets the internal power supply voltage generated by the internal power supply generation circuit based on data stored in the non-volatile memory circuit. A mode signal that switches the internal power supply voltage is set in the non-volatile memory circuit. The mode signal is set to a burn-in mode before a burn-in test and is set to a normal mode after the burn-in test. In the burn-in test, when a VCC burn-in voltage is applied to a VCC terminal to start the semiconductor device, the internal power supply generation circuit generates a VDD burn-in voltage upon receiving the mode signal set in the burn-in mode.

Semiconductor device and test method thereof

To make it possible to use a transistor with relatively low gate withstand voltage at an output stage in an apparatus including a differential amplifier. An apparatus is provided. The apparatus includes: a differential amplifier having a first current path and a second current path that form a differential pair; a first output-stage transistor that has: a first main terminal connected on a power-supply potential side; a second main terminal connected on a reference-potential side; and a control terminal connected to the second current path; and a first voltage-clamp circuit connected between the control terminal and second main terminal of the first output-stage transistor.

Apparatus comprising a differential amplifier

A reset circuit includes: an output circuit that outputs a reset release signal for releasing reset of a reset target circuit that is to be applied with a power supply voltage, when a first voltage that rises with a rise in the power supply voltage reaches a first reference voltage that rises with a rise in the power supply voltage until the first reference voltage reaches a target level; and an inhibit circuit that inhibits the reset release signal from being output to the reset target circuit until the power supply voltage reaches a third level, the third level being higher than a first level at a time when the first reference voltage exceeds the first voltage, the third level being lower than a second level at a time when the first voltage reaches the target level.

Reset circuit

In a control circuit of a switching power supply device, a switching cycle generating unit controls a switching cycle in keeping with a signal of an error voltage detected on a secondary side to stabilize an output voltage at a target value. A load current for overload protection is estimated based on a value produced by integrating a resonant current at an integrator and averaging at an averaging calculation unit. Here, although the switching cycle is correlated to the ratio of input/output voltages, the switching cycle is negatively correlated to the input voltage because the output voltage is controlled so as to be constant. A correction calculating unit uses a signal that decides the switching cycle as information corresponding to the input voltage, which eliminates the need to detect the input voltage.

Control circuit of switching power supply device

A negative power supply generates a voltage Vm that is negative when a source voltage Vh' of an activation element is used as a reference. A differential voltage between the above-described voltage Vh&#x2032; and the voltage Vm is applied to an activation circuit arranged between the activation element and a control power supply voltage Vcc. The activation circuit is configured to include a current detection resistor, a voltage conversion resister, a current source, a first PMOS switch, a second PMOS switch, and a control amplifier. The control amplifier operates in a voltage range between Vh&#x2032; and Vm, and an output of the control amplifier is connected to a gate of the first PMOS switch.

Control circuit of switching power supply, insulated switching power supply

A switching controller includes an output voltage detector that detects the output voltage of a switching power supply, a compensator, a frequency setter, a frequency sweeper, and a voltage control oscillator that are all connected in series. The switching controller also includes an ON-time generator that generates an ON time for a switching element and a pulse-width modulation signal generator that generates a pulse-width modulation signal using the output from the voltage control oscillator and the output from the ON-time generator. The frequency shifter includes a shift amount calculator that calculates a shift amount on the basis of a first coefficient that is generated by a first coefficient generator and changes as time elapses, a second coefficient generated by a second coefficient generator in accordance with the output value from the frequency setter, a third coefficient that is generated by a third coefficient generator and exhibits a different relationship with the output value from the frequency setter than the second coefficient, and the output value from the frequency setter.

Switching controller for switching power supply

A switching power supply device includes an output voltage detection unit that outputs an output voltage detection value. The control circuit includes: a target voltage generation unit that generates an output voltage setting value; an A/D conversion unit that A/D converts an error between the output voltage setting value and the output voltage detection value; a digital compensation unit that computes an amount of control based on an output signal of the A/D conversion unit; and a PWM signal generation unit that generates a PWM signal for the switching element based on the amount of control. The target voltage generation unit detects a standby state based on the output voltage detection value, the output signals of the A/D conversion unit and the digital compensation unit, and in the standby state, switches the output voltage setting value to a second value lower than a value for another state.

Switching power supply device

A control section for a current resonant converter section controls a DC output voltage of a current resonant converter section to settle to a target voltage by varying a resonant period between predetermined two resonant periods based on an error signal between the DC output voltage and the target voltage. A gain converter is provided in a preceding stage of a frequency generator for generating a square waveform signal with a duty ratio of 50% and the gain converter has a setting of a nonlinear gain characteristic that cancels nonlinearity in the input-output characteristics of the current resonant converter section. The nonlinear gain characteristic can be a characteristic of continuous gain conversion or discrete gain conversion.

Control device of a switching power supply

An output voltage error detection unit outputs an auxiliary winding voltage generated across an auxiliary winding having the same number of turns as a secondary winding a certain period after a secondary conduction period starts. A correction amount calculation unit calculates a secondary voltage drop caused by a secondary current flowing in the conduction period based on a primary current flowing when the conduction period starts and outputs a calculation result as a correction amount. A reference voltage generation unit generates a reference voltage by adding the correction amount to the output voltage. A control unit generates a feedback signal to minimize the error between the auxiliary winding voltage obtained after a certain delay period and the reference voltage. A PWM signal generation unit controls a PWM signal based on the feedback signal, adjusts switching of the switching element, and maintains the output voltage at a constant level.

Apparatus and method for controlling switching power supply

A control device of an insulation type DC/DC converter includes a shunt regulator that detects an error in output voltage at the secondary side of a transformer, a photocoupler that transmits the detected error voltage to the primary side of the transformer, and a DPWM control unit on the primary side that generates a control pulse signal having a pulse width at a duty ratio based on the error voltage. The DPWM control unit includes an A/D conversion circuit, an A/D output stabilization circuit, a dither circuit, and a DPWM circuit. The A/D output stabilization circuit is provided after the A/D conversion circuit, and the output end of the A/D output stabilization circuit is connected to the input end of the dither circuit.

Control device for switching power source

A current flowing into one of half-bridge circuits of a power semiconductor module is detected by corresponding ones of current detection circuits through a current detection terminal provided in corresponding ones of semiconductor switching devices forming the half-bridge circuits and a current detection terminal provided in corresponding ones of flywheel diodes back-to-back connected to the corresponding ones of the semiconductor switching devices. A pulse voltage waveform indicating the current detected by the corresponding ones of the current detection circuits is held for a predetermined period and converted into a stepwise voltage waveform by use of corresponding ones of sample-and-hold circuits, so that the voltage held by the corresponding ones of the sample-and-hold circuits is transmitted to a control circuit through corresponding ones of insulating circuits.

Power conversion apparatus

A switching power supply that can suppress output variation at a time of transition of a control mode from a non-linear control mode to a linear control mode. The switching power supply includes instruction value forming circuitry that forms, in a linear control mode, a linear control instruction value for linearly control a switching circuit based on an error of an output voltage, and forms, in a non-linear control mode, a non-linear control instruction value for non-linearly control the switching circuit. The instruction value forming circuitry predicts, in the non-linear control mode, a linear control instruction value suited to the load current in the non-linear control mode, and uses the predicted linear control instruction value for an initial value of the linear control instruction value at a time of transition from the non-linear control mode to the linear control mode.

Switching power supply with mode transition control

A switching regulator can convert an input voltage to a desired output voltage by ON-OFF controlling switching elements with PWM signals. The switching regulator can include a communication interface circuit that receives external operation instructions, an output voltage setting section that changes an output voltage to an output voltage setting value upon receiving an output voltage changing instruction from the outside, a voltage divider and an ADC that converts an error voltage into a digital error signal e[n], the error voltage being a difference between a reference voltage Vref and a detected output voltage value Vfb. The switching regulator can also include a controller that includes an operation control section for calculating a duty factor signal d[n] to determine an ON time proportion of the switching elements and an output voltage changing control section for controlling operation to change the output voltage.

Switching regulator performing output voltage changing function

A current-voltage conversion circuit of a current correcting unit having a current detecting terminal connected to a sense terminal of a power semiconductor device converts a sense current into a voltage and detects the voltage. A temperature detecting unit detects the ambient temperature of the power semiconductor device, and a correction unit performs a predetermined operation for correcting a characteristic difference due to the temperature on the basis of the detected temperature and outputs a control signal to a variable voltage source. The variable voltage source changes an output voltage on the basis of the output control signal and adjusts the potential of the sense terminal of the power semiconductor device on the basis of the changed voltage value. In this way, the characteristic difference between a main region and a sense region of the power semiconductor device is corrected.

Current correction circuit for power semiconductor device and current correction method

A switching power supply system controlling switching operations of switching devices by a control circuit to convert an input voltage into a desired output voltage, the system being provided with a under voltage lock out circuit including: an input voltage detection unit detecting an input voltage and producing an input voltage digital signal corresponding to the input voltage Vin; and a voltage level comparison unit carrying out digital comparison of the input voltage digital signal with each of two voltage detection level data and outputting the results of the comparisons as an output signal, in which by changing voltage detection level data stored in two registers, desired voltage detection levels and hysteresis characteristic are easily actualized.

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Matsumoto, Japan

Tetsuya Kawashima