摘要:
A control device of a plurality of switching converters is disclosed; each converter comprises at least one power switch and is associated with a control circuit of the at least one power switch. The control device comprises means suitable for comparing a signal representative of the load of the plurality of converters with a plurality of reference signals and suitable for enabling or disabling at least one of said plurality of control circuits in response to said comparison.
摘要:
A device is provided for the correction of the power factor in forced switching power supplies. The device includes a converter, and a first control circuit coupled with the converter so as to obtain a regulated voltage on the output terminal from an alternating network input voltage. The converter includes a power transistor, and the first control circuit is suitable for driving the power transistor in every switching cycle comprising the turn-on time and the turn-off time of the power transistor. The device for the correction of the power factor further includes a second control circuit coupled to the first control circuit and capable of modulating the turn-off time of the power transistor.
摘要:
The power output of a static DC--DC converter employing a current mode PWM controller is controlled upon the varying of the switching frequency, by detecting the sawtooth signal produced by the local oscillator generating a DC signal with an amplitude inversely proportional to the frequency. The power output is controlled by alternatively clamping the output voltage of the error amplifier of the PWM controller at a voltage proportional to the amplitude of the DC signal, or by offsetting the signal present on the current sensing resistor by a voltage corresponding to the difference between a constant voltage and the DC signal.
摘要:
A PWM controlled multi-phase resonant voltage converter may include a plurality of primary windings powered through respective half-bridges, and as many secondary windings connected to an output terminal of the converter and magnetically coupled to the respective primary windings. The primary or secondary windings may be connected such that a real or virtual neutral point is floating.
摘要:
The power supply device includes a DC-DC converter circuit having a power switch and a driving stage. The driving stage has a compensation terminal on which a compensation voltage is present, and which receives a biasing current. The driving stage includes a control circuit having an output terminal connected to a control terminal of the power switch and disconnection-detecting circuitry connected to the compensation terminal and generating a signal for permanent turning-off of the power switch when the biasing current drops below a current-threshold value. The driving stage moreover includes over-voltage detecting circuitry connected to the compensation terminal and generating a signal for temporary turning-off of the power switch when the compensation voltage exceeds a voltage-threshold value.
摘要:
A control device of a plurality of switching converters is disclosed; each converter comprises at least one power switch and is associated with a control circuit of the at least one power switch. The control device comprises means suitable for comparing a signal representative of the load of the plurality of converters with a plurality of reference signals and suitable for enabling or disabling at least one of said plurality of control circuits in response to said comparison.
摘要:
A device for power factor correction in a forced switching power supply unit is provided. The device includes a converter and a control device coupled to the converter so as to obtain from an input alternating mains voltage a direct regulated voltage on the output terminal. The converter includes a power transistor, and the control device includes an error amplifier having its inverting terminal coupled to a first signal that is proportional to the regulated voltage and its non-inverting terminal coupled to a reference voltage. A drive circuit of the power transistor is coupled to the output terminal of the error amplifier. The control device also includes a circuit for generating a current signal that is representative of the effective input voltage. The current signal is coupled to the inverting terminal of the error amplifier to vary the regulated voltage in reply to variations in the effective input voltage.
摘要:
A PWM controlled multi-phase resonant voltage converter may include a plurality of primary windings powered through respective half-bridges, and as many secondary windings connected to an output terminal of the converter and magnetically coupled to the respective primary windings. The primary or secondary windings may be connected such that a real or virtual neutral point is floating.
摘要:
A device for power factor correction in a forced switching power supply unit is provided. The device includes a converter and a control device coupled to the converter so as to obtain from an input alternating mains voltage a direct regulated voltage on the output terminal. The converter includes a power transistor, and the control device includes an error amplifier having its inverting terminal coupled to a first signal that is proportional to the regulated voltage and its non-inverting terminal coupled to a reference voltage. A drive circuit of the power transistor is coupled to the output terminal of the error amplifier. The control device also includes a circuit for generating a current signal that is representative of the effective input voltage. The current signal is coupled to the inverting terminal of the error amplifier to vary the regulated voltage in reply to variations in the effective input voltage.
摘要:
A converter that is directly connectable to an AC power source (e.g., the mains) includes a rectifier stage for rectifying a network voltage, a power factor correction pre-regulating circuit supplied with the rectified network voltage for producing a DC voltage of a predetermined nominal value on an output node, and a DC-DC converter. The DC-DC converter may be supplied on an input node thereof with the DC voltage of the predetermined nominal value for producing a regulated DC voltage on an output node thereof. The DC-DC converter may use a clock whose frequency is selected between at least one low and one high value by a selection signal. Furthermore, the converter may also include a stand-by circuit for producing the selection signal based upon the current delivered to the load.