Devices and methods related to boost supply for low battery 2G bias support
A voltage supply system is disclosed, comprising a boost converter configured to receive an input voltage and generate a first output voltage at a first output node, a low-voltage supply circuit configured to receive the input voltage and generate a second output voltage at a second output node, and a routing circuit configured to route the first output voltage of the boost converter to the second output node during a selected condition of the input voltage.
1. A method of operating a voltage supply system, the method comprising:
providing a boost converter configured to receive an input voltage and generate a first output voltage at a first output node;
providing a low-voltage supply circuit with a plurality of outputs configured to receive the input voltage and generate a second output voltage at a second output node among the plurality of outputs; and
providing a routing circuit configured to route the first output voltage of the boost converter to the second output node of the low-voltage supply circuit, during a selected condition of the input voltage, the routing circuit including a routing switch between the first output node and the second output node.
2. The method of claim 1 wherein the input voltage is a battery voltage Vbatt.
3. The method of claim 2 wherein the selected condition of the input voltage includes Vbatt being less than a selected value.
4. The method of claim 3 wherein the selected value is 3.0V.
5. The method of claim 3 wherein the first output voltage is a high-voltage (HV) when not in the selected condition.
6. The method of claim 5 wherein the HV output is configured as a supply voltage for an HV power amplifier (PA).
7. The method of claim 1 wherein the low-voltage supply circuit is a buck-boost converter.
8. The method of claim 1 wherein the second output voltage at the second output node is configured as a 2G supply voltage.
9. The method of claim 8 wherein the first output voltage at the first output node is configured as a 3G/4G supply voltage when not in the selected condition.
10. The method of claim 8 wherein the first output voltage at the second output node is configured as a 2G supply voltage when in the selected condition.
11. The method of claim 1 further comprising providing a controller configured to facilitate operation of the boost converter, the low-voltage supply circuit, and the routing circuit.
12. The method of claim 11 wherein the boost converter includes first and second switches configured to allow switched mode operations.
13. The method of claim 12 wherein the routing switch is configured to be controlled by the controller.
14. The method of claim 13 wherein the routing switch includes a PFET device.