초록 ▼

A soft start bridge rectifier circuit is described for controlling the operation of the bridge rectifier in order to ramp up the DC output upon connection with the AC input in order to limit in-rush current. Additionally, short-circuit/overload protection, temporary line loss protection and undervol

A soft start bridge rectifier circuit is described for controlling the operation of the bridge rectifier in order to ramp up the DC output upon connection with the AC input in order to limit in-rush current. Additionally, short-circuit/overload protection, temporary line loss protection and undervoltage checking circuitry is provided.

대표청구항 ▼

[ What is claimed is:] [1.] A rectifier circuit for converting power from an AC source having one or more phases to DC power having a voltage (Vo) from a Vo+ node to a Vo- node, the rectifier circuit comprising:at least first and second rectifier legs coupled from the Vo- node to the Vo+ node, each

[ What is claimed is:] [1.] A rectifier circuit for converting power from an AC source having one or more phases to DC power having a voltage (Vo) from a Vo+ node to a Vo- node, the rectifier circuit comprising:at least first and second rectifier legs coupled from the Vo- node to the Vo+ node, each rectifier leg including a diode and a silicon controlled rectifier (SCR), respective anodes of the diodes being coupled to the Vo- node, respective cathodes of the diodes being coupled to respective anodes of the SCRs at respective AC input nodes, and respective cathodes of the SCRs being coupled to the Vo+ node; anda gate drive circuit operable to permit one or more of the SCRs to fire at respective one or more firing angles during half cycles of respective phases of the AC source, the gate drive circuit including a ramp circuit having:a first integrator circuit operable to produce ramp pulses corresponding to respective integrals of the half cycles of the one or more phases of the AC source;a peak detector circuit operable to produce Vp;a second integrator circuit operable to produce a ramp signal (Vramp corresponding to an integal of Vp;a comparator circuit operable to produce pulsed output signals corresponding with comparisons of the respective ramp pulses with the difference of Vp and Vramp, the pulsed output signals corresponding with the respective firing angles of the SCRs,the firing angles of the gate drive circuit limiting the one or more SCRs to fire (i) only at respective firing angles between about 90.degree. to 180.degree. when Vo is below a predetermined value; and (ii) at firing angles progressively lower than 180.degree. as Vo ramps up from a voltage below the predetermined value to progressively higher values.