Patent ID: 6919756

Claim:
A voltage generation circuit, comprising: a voltage pump adapted to receive a supply voltage, the voltage pump operable to develop an output voltage responsive to a pump activation signal; and a level detection circuit adapted to receive a pump-boost signal and being coupled to the voltage pump to receive the output voltage, the level detection circuit operable in a normal mode responsive to the pump-boost signal being inactive to develop the pump activation signal to activate the voltage pump responsive to the output voltage being less than or equal to a first low threshold value, and operable in a demand-controlled mode responsive to the pump-boost signal being active to develop the pump activation signal to activate the voltage pump responsive to the output voltage being less than or equal to a second low threshold value, the level detection circuit comprising: a threshold adjustment circuit adapted to receive the pump-boost signal and being coupled to the voltage pump and to a reference voltage supply, the threshold adjustment circuit operable develop an activation voltage on a node responsive to the output voltage from the voltage pump, the activation voltage reaching a trigger value when the output voltage has a first magnitude and the pump-boost signal is active, and the activation voltage reaching the trigger value when the output voltage has a second magnitude and the pump-boost signal is inactive, the threshold adjustment circuit comprising: a plurality of resistors coupled in series between the voltage pump and a reference voltage supply, the plurality of resistors comprising a first resistor coupled between the voltage pump and the node, and second, third, and fourth resistors coupled in series between the node and the reference voltage supply; a switching circuit having signal terminals coupled in parallel with at least one of the resistors and having a control terminal adapted to receive the pump-boost signal, the switching circuit coupling the signal terminals together responsive to the pump-boost signal being active and isolating the signal terminals responsive to the pump-boost signal being inactive; and an output circuit coupled to the node of the threshold adjustment circuit and operable to activate the pump activation signal responsive to the activation voltage being less than the trigger value and operable to deactivate the pump activation signal responsive to the activation voltage being greater than the trigger value.