Method and apparatus to minimize switching noise disturbance

US9405308B2 · kind B2 · utility

Assignee

• Telefonaktiebolaget LM Ericsson (Publ) · SE

Inventors

• Mikko Lintonen · Oulu, FI
• Marko Pessa · Oulu, FI

Key dates

• Filing date: May 19, 2014
• Grant date: Aug 2, 2016
• Expiry date: Sep 28, 2034

Classification

• Technology area (CPC H): Electricity
• CPC primary: H03K17/163
• WIPO field: Control
• WIPO sector: Instruments

Abstract

A power management circuit generates a reference voltage and distributes it to a plurality of independently-enabled regulator voltage reference circuits. Separate enable signals and enable pre-charge signals are distributed to each regulator voltage reference circuit. As a regulator voltage reference circuit is enabled via its associated enable signal, an enable pre-charge signal is also asserted for an initial duration. Each regulator voltage reference circuit includes a voltage setting circuit and a first current limiting transistor in series and operative to interrupt current to the voltage setting circuit when the regulator voltage reference circuit is disabled. A second current limiting transistor is configured as a current mirror with the first current limiting transistor, and a pre-charge bias current from a current source passes through the second transistor. This limits the current through the first transistor and into the voltage setting circuit for the initial duration.