Multi-element driver topology for element selection

Abstract

Apparatuses including multiple selectable circuit elements are described. In an example, an apparatus may include a power supply configured to output a voltage. The apparatus may further include a controller connected to the power supply and a transmission unit connected to the controller. The transmission unit may be configured to output power. The transmission unit may include comprising an inverter connected to the power supply. The inverter may include a high-side switching element. The transmission unit may further include a circuit element a circuit connected to the power supply. The circuit may be configured to select the circuit element. The circuit may include a switch connected between the inverter and the circuit element. The switch and the high-side switching element may be configured to be driven by the voltage outputted by power supply. The controller may be configured to control the power being outputted by the transmission unit.

What is claimed is: 
     
         1 . An apparatus comprising:
 a circuit connected to a capacitor connected between an inverter and a coil, the circuit comprising a selection switch connected between the inverter and the capacitor, wherein:
 in response to a voltage being applied to a gate of the selection switch, the selection switch is driven to an on state to connect the capacitor to the inverter, and the voltage is same as a voltage being used for driving a high-side switching element of the inverter; and 
 in response to a fraction of the voltage being applied to the gate of the selection switch, the selection switch is driven to an off state to disconnect the capacitor from the inverter. 
   
     
     
         2 . The apparatus of  claim 1 , further comprising a switch connected between the inverter and ground, wherein:
 the switch is configured to receive a selection signal indicating whether the capacitor is being selected or deselected;   in response to the selection signal indicating the capacitor is being deselected, the switch is maintained in an off state to cause the voltage to be applied to the gate of the selection switch to drive the selection switch to an on state; and   in response to the selection signal indicating the capacitor is being selected, the switch is driven to an on state to cause the fraction of the voltage to be applied to the gate of the selection switch to drive the selection switch to an off state.   
     
     
         3 . The apparatus of  claim 1 , wherein:
 the capacitor is a first capacitor;   a second capacitor is connected between the inverter and the coil, the second capacitor and the coil form a resonant circuit; and   in response to the first capacitor being connected, the first capacitor is switched into the resonant circuit.   
     
     
         4 . The apparatus of  claim 1 , wherein:
 the circuit is a first circuit;   the capacitor is a first capacitor;   the coil is a first coil;   the selection switch is a first selection switch;   the high-side switching element is a first high-side switching element;   the voltage is a first voltage;   the apparatus further comprises a second circuit connected to a second capacitor connected between the inverter and a second coil, the second circuit comprising a second selection switch connected between the inverter and the second capacitor, wherein:
 in response to a second voltage being applied to a gate of the second selection switch, the second selection switch is driven to an on state to connect the second capacitor to the inverter, and the second voltage is same as a voltage being used for driving a second high-side switching element of the inverter; and 
 in response to a fraction of the second voltage being applied to the gate of the second selection switch, the second selection switch is driven to an off state to disconnect the second capacitor from the inverter. 
   
     
     
         5 . The apparatus of  claim 1 , wherein the circuit further comprises a voltage divider, and the circuit is configured to:
 in response to an indication that the capacitor is being deselected, activate the voltage divider to reduce the voltage down to the fraction of the voltage.   
     
     
         6 . The apparatus of  claim 1 , wherein the circuit further comprises a PNP transistor, and the circuit is configured to:
 in response to an indication that the capacitor is being deselected, activate the PNP transistor to reduce the voltage down to the fraction of the voltage.   
     
     
         7 . The apparatus of  claim 1 , wherein the circuit is a part of a wireless power transmitter. 
     
     
         8 . An apparatus comprising:
 an inverter including a high-side switching element;   a capacitor;   a coil; and   a circuit between the inverter and the coil, the circuit comprising a selection switch connected between the inverter and the capacitor, wherein:
 in response to a voltage being applied to a gate of the selection switch, the selection switch is driven to an on state to connect the capacitor to the inverter, and the voltage is same as a voltage being used for driving a high-side switching element of the inverter; and 
 in response to a fraction of the voltage being applied to the gate of the selection switch, the selection switch is driven to an off state to disconnect the capacitor from the inverter. 
   
     
     
         9 . The apparatus of  claim 8 , further comprising a switch connected between the inverter and ground, wherein:
 the switch is configured to receive a selection signal indicating whether the capacitor is being selected or deselected;   in response to the selection signal indicating the capacitor is being deselected, the switch is maintained in an off state to cause the voltage to be applied to the gate of the selection switch to drive the selection switch to an on state; and   in response to the selection signal indicating the capacitor is being selected, the switch is driven to an on state to cause the fraction of the voltage to be applied to the gate of the selection switch to drive the selection switch to an off state.   
     
     
         10 . The apparatus of  claim 8 , wherein:
 the capacitor is a first capacitor;   a second capacitor is connected between the inverter and the coil, the second capacitor and the coil form a resonant circuit; and   in response to the first capacitor being connected, the first capacitor is switched into the resonant circuit.   
     
     
         11 . The apparatus of  claim 8 , wherein:
 the circuit is a first circuit;   the capacitor is a first capacitor;   the coil is a first coil;   the selection switch is a first selection switch;   the high-side switching element is a first high-side switching element;   the voltage is a first voltage;   the apparatus further comprises a second circuit connected to a second capacitor connected between the inverter and a second coil, the second circuit comprising a second selection switch connected between the inverter and the second capacitor, wherein:
 in response to a second voltage being applied to a gate of the second selection switch, the second selection switch is driven to an on state to connect the second capacitor to the inverter, and the second voltage is same as a voltage being used for driving a second high-side switching element of the inverter; and 
 in response to a fraction of the second voltage being applied to the gate of the second selection switch, the second selection switch is driven to an off state to disconnect the second capacitor from the inverter. 
   
     
     
         12 . The apparatus of  claim 8 , wherein the circuit further comprises a voltage divider, and the circuit is configured to:
 in response to an indication that the capacitor is being deselected, activate the voltage divider to reduce the voltage down to the fraction of the voltage.   
     
     
         13 . The apparatus of  claim 8 , wherein the circuit further comprises a PNP transistor, and the circuit is configured to:
 in response to an indication that the capacitor is being deselected, activate the PNP transistor to reduce the voltage down to the fraction of the voltage.   
     
     
         14 . The apparatus of  claim 8 , wherein the inverter, the capacitor, the coil and the circuit are parts of a wireless power transmitter. 
     
     
         15 . An apparatus comprising:
 a power supply configured to output a voltage;   a controller connected to the power supply;   a transmission unit connected to the controller, the transmission unit being configured to output power, and the transmission unit comprising:
 an inverter including a high-side switching element; 
 a capacitor; 
 a coil; and 
 a circuit between the inverter and the coil, the circuit comprising a selection switch connected between the inverter and the capacitor, wherein:
 in response to a voltage being applied to a gate of the selection switch, the selection switch is driven to an on state to connect the capacitor to the inverter, and the voltage is same as a voltage being used for driving a high-side switching element of the inverter; and 
 in response to a fraction of the voltage being applied to the gate of the selection switch, the selection switch is driven to an off state to disconnect the capacitor from the inverter. 
 
   
     
     
         16 . The apparatus of  claim 15 , wherein the transmission unit further comprises a switch connected between the inverter and ground, wherein:
 the switch is configured to receive a selection signal indicating whether the capacitor is being selected or deselected;   in response to the selection signal indicating the capacitor is being deselected, the switch is maintained in an off state to cause the voltage to be applied to the gate of the selection switch to drive the selection switch to an on state; and   in response to the selection signal indicating the capacitor is being selected, the switch is driven to an on state to cause the fraction of the voltage to be applied to the gate of the selection switch to drive the selection switch to an off state.   
     
     
         17 . The apparatus of  claim 15 , wherein:
 the capacitor is a first capacitor;   a second capacitor is connected between the inverter and the coil, the second capacitor and the coil form a resonant circuit; and   in response to the first capacitor being connected, the first capacitor is switched into the resonant circuit.   
     
     
         18 . The apparatus of  claim 15 , wherein:
 the circuit is a first circuit;   the capacitor is a first capacitor;   the coil is a first coil;   the selection switch is a first selection switch;   the high-side switching element is a first high-side switching element;   the voltage is a first voltage;   the transmission unit further comprises a second circuit connected to a second capacitor connected between the inverter and a second coil, the second circuit comprising a second selection switch connected between the inverter and the second capacitor, wherein:
 in response to a second voltage being applied to a gate of the second selection switch, the second selection switch is driven to an on state to connect the second capacitor to the inverter, and the second voltage is same as a voltage being used for driving a second high-side switching element of the inverter; and 
 in response to a fraction of the second voltage being applied to the gate of the second selection switch, the second selection switch is driven to an off state to disconnect the second capacitor from the inverter. 
   
     
     
         19 . The apparatus of  claim 15 , wherein the circuit further comprises a voltage divider, and the circuit is configured to:
 in response to an indication that the capacitor is being deselected, activate the voltage divider to reduce the voltage down to the fraction of the voltage.   
     
     
         20 . The apparatus of  claim 15 , wherein the circuit further comprises a PNP transistor, and the circuit is configured to:
 in response to an indication that the capacitor is being deselected, activate the PNP transistor to reduce the voltage down to the fraction of the voltage.