US 12,278,623 B2
Power on reset (POR) circuit
Henricus Cornelis Johannes Büthker, Mierlo (NL); Jyotirmoy Ghosh, Kolkata (IN); Piotr Gibas, Eindhoven (NL); Edwin Schapendonk, Oss (NL); Neha Goel, Noida (IN); and Namith Vishnu N, Aluva (IN)
Assigned to NXP B.V., Eindhoven (NL)
Filed by NXP B.V., Eindhoven (NL)
Filed on Jun. 9, 2023, as Appl. No. 18/332,522.
Claims priority of application No. 202341028665 (IN), filed on Apr. 20, 2023.
Prior Publication US 2024/0356543 A1, Oct. 24, 2024
Int. Cl. H03K 17/22 (2006.01); H03K 3/037 (2006.01)
CPC H03K 17/223 (2013.01) [H03K 3/037 (2013.01)] 21 Claims
OG exemplary drawing
 
1. A power on reset (POR) circuit, comprising:
a power supply input configured to be coupled to a power supply voltage;
a capacitor having a first end coupled to a reference potential;
a resistor divider having a set of tap points, wherein at least one tap point is coupled to the reference potential;
a comparator coupled to the power supply input and the reference potential, and having a comparator threshold dependent upon the power supply voltage;
a first circuit coupled to a second end of the capacitor and configured to couple the power supply input to the resistor divider when a voltage on the second end of the capacitor is below a first circuit threshold;
wherein the first circuit is configured to un-couple the power supply input from the resistor divider when the voltage on the second end of the capacitor is above the first circuit threshold;
a second circuit configured to couple the second end of the capacitor to the power supply input when a voltage on at least one tap point of the resistor divider is above a second circuit threshold;
wherein the comparator is coupled to at least one of the tap points, the reference potential, and a POR output; and
wherein the comparator is configured to ramp-up a POR signal on the POR output when a voltage on the at least one of the tap points is greater than the comparator threshold.