TPS5206CN

SWITCHING-POWER-SUPPLY CONTROL CIRCUIT

SLVS082A – APRIL 1994 – REVISED SEPTEMBER 1994

Copyright

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POST OFFICE BOX 655303

POST OFFICE BOX 1443

Control With Limited External Components

Transformer

and Latch-Up for Each Supply Voltage:

5 V, 12 V, – 5 V, and – 12 V

description

The TPS5206CN is a bipolar monolithic integrated circuit designed for push-pull-type switching-power-supply

(SPS) control in desktop PC applications. It offers pulse-width-modulation (PWM) control and power-supply

supervisor functions, including detection of undervoltage and overvoltage conditions on

±5 V and ±12 V system

supplies. It also detects overcurrent conditions on the SPS system output. This single chip reduces the total

component count and provides additional design flexibility, which minimizes cost and printed-circuit-board

(PCB) space requirements in present and new SPS designs.

overvoltage-protection lockout feature

The overvoltage-protection lockout feature monitors four different supply voltages. When an overvoltage (OV)

condition is detected, the power-good output (PGO) is set low and the PWM function is disabled. The OV

condition is detected on the SVP5, SVP12, SVN5, and SVN12 inputs. Threshold voltages are typically 5.9 V,

14.1 V, – 8.4 V, and – 15.3 V, respectively.

undervoltage-protection lockout feature

The undervoltage-protection lockout feature monitors four different supply voltages. When an undervoltage

(UV) condition is detected, the power-good output (PGO) is set low and the PWM function is disabled. The UV

condition is detected on the SVP5, SVP12, SVN5, and SVN12 inputs. Threshold voltages are typically 3.9 V,

9.5 V, – 3.4 V, and – 9.3 V, respectively.

overcurrent-protection lockout feature

The overcurrent (OC) protection lockout feature is designed to protect the SPS from excessive load or

short-circuit conditions. The circuit converts the output current of the SPS to a voltage, which is then monitored

at SC. It sets PG low and shuts down the PWM circuit when the sensed voltage is higher than 5 V.

reference regulator

The internal 5-V reference regulator is designed primarily to provide the internal circuitry with a stable supply

rail for varying input voltages. The regulator employs a band-gap circuit as its primary reference to maintain

thermal stability of less than 100-mV variation over the operating free-air temperature range of 0

°C to 70°C. In

addition to supplying an internal reference, the regulator provides a precision 5-V reference that can support

5 mA of load current for external bias circuits. The regulated voltage has a margin of error of 2%. Short-circuit

protection is provided to protect the internal circuit from overload or short-circuit conditions.

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REF

PGO

SVP5

SVP12

CPR

DT

CUV

SVN5

SVN12

D1

CPG

PGI

EA +

EA –

EAO

SC

CT

D2

GND

N PACKAGE

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PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of Texas Instruments

standard warranty. Production processing does not necessarily include

testing of all parameters.