1 Features

1• Internal Series-Pass and Step-Up Switching

Regulator

• Output Adjustable From 2.9 V to 30 V

• 1-V to 10-V Input for Switching Regulator

• 4.5-V to 32-V Input for Series Regulator

• Externally Controlled Switching Current

• No External Rectifier Required

2 Applications

• Voltage Boosting

• Dual-Supply Voltage Reglation AC•

Battery Back-Ups

• Microprocessor Memory Power

3 Description

The TL499A device is an integrated circuit designed

to provide a wide range of adjustable regulated

supply voltages. The regulated output voltage can be

varied from 2.9 V to 30 V by adjusting two external

resistors. When the TL499A is ac-coupled to line

power through a step-down transformer, it operates

as a series DC voltage regulator to maintain the regulated output voltage. With the addition of a

battery from 1.1 V to 10 V, an inductor, a filter

capacitor, and two resistors, the TL499A operates as

a step-up switching regulator during an AC-line

failure. The adjustable regulated output voltage makes the TL499A useful for a wide range of

applications. Providing backup power during an AC•

line failure makes the TL499A extremely useful in

microprocessor memory applications. The TL499AC

is characterized for operation from –20°C to +85°C.