Variable gain charge pump controller
A variable gain charge pump controller includes a switching network connected to three external capacitors: a first input capacitor, a second input capacitor and an output capacitor. Two of these capacitors (the first input capacitor and the output capacitor) are connected between the controller and ground. Both terminals of the second input capacitor are also connected to the controller bringing the total number of pins required (with pins for power and ground) to six. The first input capacitor is continuously charged with a voltage αV AMP , which can be a function of the input voltage or the output voltage. The controller operates in an alternating sequence that includes a phase where the input capacitors are connected in series between the ground voltage and the output node, and a phase where the second input capacitor is connected between the ground voltage and the input voltage.
1 . A charge pump for increasing an input voltage, the charge pump comprising:
an output capacitor connected between a ground voltage and an output node;
a first input capacitor connected between the ground voltage and a voltage V AMP ;
a second input capacitor;
a switching network configured to control operation of the capacitors in an alternating sequence that includes:
a first phase where the second input capacitor is connected between the ground voltage and the input voltage; and
a second phase where the input capacitors are connected in series between the ground voltage and the output node.
2 . A charge pump as recited in claim 1 in which the voltage V AMP is a fraction of the input voltage.
3 . A charge pump as recited in claim 1 in which the voltage V AMP is an adaptive function of the voltage required by a device driven by the charge pump.
4 . A charge pump controller for increasing an input voltage, the charge pump controller comprising:
a switching network configured to be connected to an output capacitor, a first input capacitor and a second input capacitor using no more than four I/O pins;
the switching network configured so that the output capacitor is connected between a ground voltage and an output node;
the first input capacitor is connected between the ground voltage and a voltage V AMP ;
with the switching network configured to control operation of the capacitors in an alternating sequence that includes:
a first phase where the second input capacitor is connected between the ground voltage and the input voltage; and
a second phase where the input capacitors are connected in series between the ground voltage and the output node.
5 . A charge pump controller as recited in claim 4 in which the voltage V AMP is a fraction of the input voltage.
6 . A charge pump controller as recited in claim 4 in which the voltage V AMP is an adaptive function of the voltage required by a device driven by the charge pump controller.
7 . A charge pump controller that comprises:
a switching network;
a first I/O pin configured allow an output capacitor to be connected between a ground voltage and an output node of the switching network;
a second I/O pin configured to allow a first input capacitor to be connected between the ground voltage and a voltage V AMP ;
third and fourth I/O pins allowing the anode and cathode of a second input capacitor to be connected to the switching network
where the switching network is configured to control operation of the capacitors in an alternating sequence that includes:
a first phase where the second input capacitor is connected between the ground voltage and the input voltage; and
a second phase where the input capacitors are connected in series between the ground voltage and the output node.
7 . A charge pump controller as recited in claim 6 in which the voltage V AMP is a fraction of the input voltage.
8 . A charge pump controller as recited in claim 6 in which the voltage V AMP is an adaptive function of the voltage required by a device driven by the charge pump controller.
9 . A method for increasing an input voltage to an output voltage, the method comprising:
connecting an output capacitor between a ground voltage and an output node;
connecting a first input capacitor between the ground voltage and a voltage V AMP ;
operating a switching network in an alternating sequence that includes:
a first phase where the second input capacitor is connected between the ground voltage and the input voltage; and
a second phase where the first input capacitor and a second input capacitor are connected in series between the ground voltage and the output node.
10 . A method as recited in claim 9 in which the voltage V AMP is a fraction of the input voltage.
11 . A method as recited in claim 9 in which the voltage V AMP is an adaptive function of the voltage required by a device driven by the output voltage.