The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 17, 2003
Filed:
May. 08, 2002
Ronald Neal Dow, San Jose, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A low current open loop voltage regulator monitor. A circuit is formed with a PTAT current source across a resistor. This current is mirrored by a circuit with two outputs. A first output is formed by a high output impedance current source that has a cascode output. A second output is formed by a higher voltage output current source that has a lower output impedance. The second output feeds an emitter of a PNP device that has its base coupled to the output of the first current source. The output of the first current source and the base of the PNP device are biased above ground by a series of diode and resistor drops that are of the same type comprising the PTAT circuit. This series of devices forms a stack of bandgap voltages that is nominally equal to, but independent of, the regulator output voltage. The emitter of the PNP device is coupled to the base of a transistor whose emitter is coupled to the regulated output, forming a “super charge” circuit that biases the regulator in response to a sudden increase in load current. In this novel manner, a regulated voltage supply may be independently monitored, and a supercharge or boost current source may be switched in to support the voltage supply under high load situations, providing faster and better response to load variations than is characteristic for regulated supplies under the prior art.