Rectifier less bidirectional AC to DC converter
First Claim
1. A rectifier less ac to dc converter comprising:
- an ac power source having an ac input node and a ground node; and
a small resistance value sense resistor coupled between the said ac input node and a voltage sense node; and
a high frequency current bypass capacitor is coupled between said voltage sense node and the said ground node; and
a power inductor is connected between said voltage sense node and a switching output node; and
a power pmos transistor having a pmos source is connected to a positive vcc voltage node, and having a pmos drain is connected to the said switching output node, and having a pmos gate node; and
a power nmos transistor having a nmos source is connected to a negative vee voltage node, and having a nmos drain is connected to the said switching output node, and having a nmos gate node; and
a pulse width modulation generation circuit couples a pair of low supply current shoot through gate voltage switching signals to the said pmos gate node and the said nmos gate node ; and
the said pulse width modulation generation circuit has an effective duty cycle which defines the voltage at the said voltage sense node; and
an input current measuring means is connected across the said small resistance value sense resistor; and
said input current measuring means adjusts the said effective duty cycle of the said pulse width modulation generation circuit;
such thata secondary ac output coil sees an equivalent load impedance connected across it which has a current to voltage relationship to be that of an equivalent simulated resistor; and
an efficient power transfer takes place between the said secondary ac output coil, into the said equivalent simulated resistor, and on to both equally the said positive vcc voltage node and the said negative vee voltage node.
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Accused Products
Abstract
A split supply DC to DC converter is coupled through a low resistance path to a secondary coil of an ac line transformer, and is used as a high efficiency bidirectional AC to DC convertor. A small sense resistor is placed in series with the secondary in order to measure secondary current. The duty cycle of the DC to DC converter, which defines the voltage of what is normally treated as an output node, is modulated by the monitored secondary current. By coupling such an output node across the secondary coil, a voltage to current relationship is defined across the secondary to be that of a simulated resistor. Such a resistor will absorb power from the AC line and transfer it efficiently to the split supplies. The power transfer direction is reversed with the same efficiency by defining the current to voltage relationship to be one of a negative resistor.
29 Citations
12 Claims
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1. A rectifier less ac to dc converter comprising:
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an ac power source having an ac input node and a ground node; and a small resistance value sense resistor coupled between the said ac input node and a voltage sense node; and a high frequency current bypass capacitor is coupled between said voltage sense node and the said ground node; and a power inductor is connected between said voltage sense node and a switching output node; and a power pmos transistor having a pmos source is connected to a positive vcc voltage node, and having a pmos drain is connected to the said switching output node, and having a pmos gate node; and a power nmos transistor having a nmos source is connected to a negative vee voltage node, and having a nmos drain is connected to the said switching output node, and having a nmos gate node; and a pulse width modulation generation circuit couples a pair of low supply current shoot through gate voltage switching signals to the said pmos gate node and the said nmos gate node ; and the said pulse width modulation generation circuit has an effective duty cycle which defines the voltage at the said voltage sense node; and an input current measuring means is connected across the said small resistance value sense resistor; and said input current measuring means adjusts the said effective duty cycle of the said pulse width modulation generation circuit;
such thata secondary ac output coil sees an equivalent load impedance connected across it which has a current to voltage relationship to be that of an equivalent simulated resistor; and an efficient power transfer takes place between the said secondary ac output coil, into the said equivalent simulated resistor, and on to both equally the said positive vcc voltage node and the said negative vee voltage node. - View Dependent Claims (4, 5, 6, 7)
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2. A rectifier less ac to dc converter comprising:
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an ac line transformer having a primary ac input coil and a secondary ac output coil; and a small resistance value sense resistor connected in series with the said secondary ac output coil; and a first secondary coil node of the said secondary ac output coil is coupled through a first low resistance path to a ground node, and a second secondary coil node of said secondary ac output coil is coupled through a second low resistance path to a voltage sense node; and a high frequency current bypass capacitor is coupled between said voltage sense node and the said ground node; and a power inductor is connected between said voltage sense node and a switching output node; and a power pmos transistor having a pmos source is connected to a positive vcc voltage node, and having a pmos drain is connected to the said switching output node, and having a pmos gate node; and a power nmos transistor having a nmos source is connected to a negative vee voltage node, and having a nmos drain is connected to the said switching output node, and having a nmos gate node; and a pulse width modulation generation circuit couples a pair of low supply current shoot through gate voltage switching signals to the said pmos gate node and the said nmos gate node; and the said pulse width modulation generation circuit has an effective duty cycle which defines the voltage at the said voltage sense node; and an input current measuring means is connected across the said small resistance value sense resistor; and the said input current measuring means adjusts the said effective duty cycle of the said pulse width modulation generation circuit;
such thatthe said secondary ac output coil sees an equivalent load impedance connected across it which has a current to voltage relationship to be that of an equivalent simulated resistor; and an efficient power transfer takes place between the said secondary ac output coil, into the said equivalent simulated resistor, and on to both equally the said positive vcc voltage node and the said negative vee voltage node. - View Dependent Claims (8, 9, 10, 11)
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3. A rectifier less bidirectional ac to dc converter comprising:
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an ac line transformer having a primary ac input coil and a secondary ac output coil; and a small resistance value sense resistor connected in series with the said secondary ac output coil; and a first secondary coil node of the said secondary ac output coil is coupled through a first low resistance path to a ground node, and a second secondary coil node of said secondary ac output coil is coupled through a second low resistance path to a voltage sense node; and a high frequency current bypass capacitor is coupled between said voltage sense node and the said ground node; and a power inductor is connected between said voltage sense node and a switching output node; and a power pmos transistor having a pmos source is connected to a positive vcc voltage node, and having a pmos drain is connected to the said switching output node, and having a pmos gate node; and a power nmos transistor having a nmos source is connected to a negative vee voltage node, and having a nmos drain is connected to the said switching output node, and having a nmos gate node; and a pulse width modulation generation circuit couples a pair of low supply current shoot through gate voltage switching signals to the said pmos gate node and the said nmos gate node; and the said pulse width modulation generation circuit has an effective duty cycle which defines the voltage at the said voltage sense node; and an input current measuring means is connected across the said small resistance value sense resistor, and a secondary coil voltage measuring means is connected across secondary ac output coil; and the said effective duty cycle of the said pulse width modulation generation circuit is adjusted by the product of a measured input voltage of said secondary voltage measuring means times an adjustable gain level;
such thata reference magnitude of the said adjustable gain level causes the to said voltage sense node and the said secondary ac output coil to have equal ac voltage; and a decrease in magnitude of the said adjustable reference gain level below the said reference magnitude results in the transfer of power from said secondary ac output coil to the said positive vcc voltage node and the said negative vee voltage node; and an increase in magnitude of the said adjustable reference gain level above the said reference magnitude results in the transfer of power from the said positive vcc voltage node to the said secondary ac output coil. - View Dependent Claims (12)
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Specification