Charge pump and control scheme
View Patent ↗A switch controller has a charge pump, a selector switch connected to the charge pump, and a pre-charge power supply input connectable to the input of the selector switch. For each of the output channels being controlled, a power control switch is connected to an output of the selector switch. In response to commands, output channels are enabled and disabled, causing corresponding actions in the power control switches. When an output channel is to be activated, the output channel is selected by the selector switch and the pre-charge power supply connected to the input of the selector switch. The charging is completed by the charge pump and the enabled status of the power control switch is maintained by the charge pump.
1. A switch controller comprising:
a charge pump configured to provide a first charge voltage;
a selector switch, an input of the selector switch connected to the charge pump and the selector switch operable to connect to an output channel for charging the output channel; and
a power source connection communicating with the input to the selector switch, wherein the power source connection provides power at a second charge voltage, wherein the second charge voltage is less than the first charge voltage, wherein during an enablement of the channel from a disabled state, the selector switch provides power from the power source connection to charge the output channel from a disabled state to a voltage below the first charge voltage and subsequently provides power from the charge pump to charge the output channel to the first charge voltage.
2. The switch controller as in claim 1 , wherein the selector switch is one of a plurality of first switches, each of the plurality of first switches operable to connect to one of a plurality of output channels to enable the one of the plurality of output channels with charge current from the power source connection and from the charge pump, and an input of each of the plurality of first switches connected with the charge pump.
3. The switch controller as in claim 1 , wherein the selector switch is implemented in a multi-channel switch circuit, an output of the multi-channel selector switch circuit operable to connect to one of a plurality of output channels.
4. The switch controller as in claim 1 , wherein the power source connection communicates with the input of the selector switch through a power source switch.
5. The switch controller as in claim 1 , wherein the charge pump is operable at a high clock rate and a low clock rate.
6. The switch controller as in claim 5 , wherein the high clock rate and the low clock rate are selectable by a control circuit.
7. The switch controller as in claim 6 , wherein the charge pump operates at the high clock rate when the output channel is being enabled.
8. The switch controller in claim 1 , wherein an external load capacitance is used as an output capacitor of the charge pump.
9. The switch controller as in claim 1 , further comprising a power dump switch, an input of said power dump switch connectable to the output channel and an output of said power dump switch connected to a ground.
10. The switch controller as in claim 9 , wherein the power dump switch is one of a plurality of second switches, each of the plurality of second switches having an input connectable to one output channel of a plurality of output channels, and each of the plurality of second switches having an output connected to the ground.
11. The switch controller as in claim 1 , further comprising a digital control circuit, wherein the digital control circuit has an output flag indicating the status of each output channel.
12. The switch controller as in claim 1 , wherein a status of the output channel is determined by measuring a voltage of the output channel.
13. The switch controller according to claim 1 , wherein more than one output channel is enabled simultaneously in response to commands received by a digital control circuit.
14. A switch controller comprising:
a charge pump;
a selector switch, an input of the selector switch connected to the charge pump and the selector switch operable to connect to an output channel; and
a power source connection communicating with the input to the selector switch;
wherein a status of the output channel is determined by measuring a voltage of the output channel;
wherein the voltage measuring circuit comprises:
a resistive voltage divider;
a capacitive voltage divider;
a comparator communicating with the resistive voltage divider and the capacitive voltage divider.
15. A method of controlling a system, the method comprising:
selecting a channel of a multi-channel system to be enabled;
connecting a power supply to the channel to be enabled to charge the channel with the power supply from a disabled state;
disconnecting the power supply to the channel to be enabled wherein when disconnected, the channel is charged to a first voltage; and
operating a charge pump connected the channel to be enabled to charge the channel to a higher voltage than the first voltage.
16. A method of controlling a system, the method comprising:
selecting a channel of a multi-channel system to be enabled;
connecting a power supply to the channel to be enabled;
disconnecting the power supply to the channel to be enabled; and
operating a charge pump connected the channel to be enabled;
wherein the disconnecting the power supply corresponds to the expiration of a timer.
17. The method of claim 15 , wherein the charge pump is operable at a high clock rate between the disconnecting the power supply and completion of enabling the channel.
18. The method of claim 15 , wherein the completion of enabling the output channel is determined by a measurement of a voltage on the channel to be enabled.
19. A method of controlling a system, the method comprising:
selecting a channel of a multi-channel system to be enabled;
connecting a power supply to the channel to be enabled;
disconnecting the power supply to the channel to be enabled; and
operating a charge pump connected the channel to be enabled;
wherein the completion of enabling the output channel is determined by a measurement of a voltage on the channel to be enabled;
wherein the method further comprises providing a comparator, a resistive divider and a capacitive divider, and measuring the voltage of the channel to be enabled using the resistive voltage divider and comparator when the power supply is connected to the channel to be enabled, and measuring the voltage of the channel to be enabled using the capacitive voltage divider when the power supply is disconnected from the channel to be enabled.
20. The method of claim 15 , wherein the channel is disabled by deselecting the channel and connecting the channel to a ground.
21. The method of claim 15 , wherein more than one channel is enabled simultaneously.
22. The method of claim 15 , wherein when a first output channel is being enabled, a second output channel being enabled is delayed until the enabling of the first output channel has been completed.