US 12,216,487 B2
Protection voltage generating circuit with monotonic and stable power supply voltage behavior
Angel C. Abusleme Hoffman, Austin, TX (US); and Axel Thomsen, Austin, TX (US)
Assigned to CIRRUS LOGIC, INC., Austin, TX (US)
Filed by CIRRUS LOGIC INTERNATIONAL SEMICONDUCTOR LTD., Edinburgh (GB)
Filed on Dec. 8, 2022, as Appl. No. 18/077,402.
Prior Publication US 2024/0192715 A1, Jun. 13, 2024
Int. Cl. G05F 1/571 (2006.01); G05F 1/46 (2006.01)
CPC G05F 1/571 (2013.01) [G05F 1/461 (2013.01); G05F 1/465 (2013.01)] 24 Claims
OG exemplary drawing
 
1. A circuit for generating a protection voltage, comprising:
a first circuit for generating a first voltage from a power supply voltage;
a second circuit that generates a second voltage from the power supply voltage, wherein the first voltage and the second voltage have a differing dependence on the power supply voltage so that a difference between the first voltage and the second voltage changes sign for a particular value of the power supply voltage;
a first amplifier circuit having an input coupled to an output of the first circuit and that receives the first voltage, wherein the first amplifier circuit generates a first output voltage;
a second amplifier circuit having an input coupled to an output of the second circuit and that receives the second voltage, wherein the second amplifier circuit generates a second output voltage, wherein the first amplifier circuit provides negative feedback to the second amplifier circuit, and wherein the second amplifier circuit provides negative feedback to the first amplifier circuit; and
an output circuit that receives the first output voltage from the first amplifier circuit and the second output voltage from the second amplifier circuit and generates the protection voltage according to a maximum or a minimum value among the first output voltage and the second output voltage, so that the protection voltage is monotonic with respect to variation of the power supply voltage in a region of the power supply voltage including the particular value of the power supply voltage.