TEA1211 Ver la hoja de datos (PDF) - Philips Electronics

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componentes Descripción

Fabricante

TEA1211

High efficiency auto-up/down DC/DC converter

Philips Electronics 

Philips Semiconductors

High efficiency auto-up/down

DC/DC converter

handbook, halfpage

n.c. 8

GND 7

n.c. 6

GND 5

LXA 4

LXA 3

IN 2

LXA 1

TEA1211HN

17 n.c.

18 GND

19 n.c.

20 GND

21 LXB

22 LXB

23 OUT

24 LXB

MDB002

Preliminary specification

TEA1211HN

This diagram is a bottom side view.

Pin 1 is indicated with a dot on the top side of the package.

For mechanical details of HVQFN32 package, see Chapter 12.

Fig.2 Pin configuration.

7 FUNCTIONAL DESCRIPTION

7.1 Introduction

The TEA1211HN is able to operate in Pulse Frequency

Modulation (PFM) or discontinuous conduction mode as

well as in Pulse Width Modulation (PWM) or continuous

conduction mode. All switching actions are completely

determined by a digital control circuit which uses the

output voltage level as control input. This digital approach

enables the use of a new pulse width and frequency

modulation scheme, which ensures optimum power

efficiency over the complete range of operation of the

converter.

7.2 Control mechanism

Depending on load current Iload and VIN to VOUT ratio, the

controller chooses a mode of operation. When high output

power is requested, the device will operate in PWM

(continuous conduction) mode, which is a 2-phase cycle in

up- as well as in down mode. For small load currents the

controller will switch over to PFM (discontinuous mode),

which is either a 3- or 4-phase cycle depending on the

input to output ratio, see Fig.3.

handbook, halfpage

Icoil

PWM

PFM

0

VIN > VOUT

down mode

VIN = VOUT

stationary mode

VIN < VOUT

up mode

MDB003

Fig.3 Waveform of coil current as function of Iload

and VIN to VOUT ratio.

2003 Oct 13

5

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