TPS2205

DUAL-SLOT PC CARD POWER-INTERFACE SWITCH

FOR PARALLEL PCMCIA CONTROLLERS

SLVS128D OCTOBER 1995 – REVISED JUNE 1998

24

POST OFFICE BOX 655303

APPLICATION INFORMATION

12-V flash memory supply

The TPS6734 is a fixed 12-V output boost converter capable of delivering 120 mA from inputs as low as

2.7 V. The device is pin-for-pin compatible with the MAX734 regulator and offers the following advantages: lower

supply current, wider operating input-voltage range, and higher output currents. As shown in Figure 1, the only

external components required are: an inductor, a Schottky rectifier, an output filter capacitor, an input filter

space when implemented with surface-mount components. An enable input is provided to shut the converter

down and reduce the supply current to 3

µA when 12 V is not needed.

The TPS6734 is a 170-kHz current-mode PWM ( pulse-width modulation) controller with an n-channel MOSFET

power switch. Gate drive for the switch is derived from the 12-V output after start-up to minimize the die area

needed to realize the 0.7-

Ω MOSFET and improve efficiency at input voltages below 5 V. Soft start is

accomplished with the addition of one small capacitor. A 1.22-V reference (pin 2) is brought out for external use.

For additional information, see the TPS6734 data sheet (SLVS127).

VCC

FB

OUT

GND

EN

REF

SS

COMP

1

2

3

4

8

7

6

5

TPS6734

3.3 V or 5 V

ENABLE

(see Note A)

+

33

µF, 20 V

L1

18

µH

12 V

C5

D1

U1

C4 0.001

µF

+

C1

C2

0.01

µF

R1

10 k

Ω

33

µF, 20 V

A_VCC5

A_VCC3

A_VPP_VCC

A_VPP_PGM

B_VCC5

B_VCC3

B_VPP_VCC

B_VPP_PGM

AVCC

AVCC

AVCC

BVCC

BVCC

BVCC

AVPP

AVPP

BVPP

BVPP

3.3V

3.3 V

To CPU

OC

5V

5 V

GND

3.3V

5V

3.3V

5V

12V

12V

TPS2205

1

µF

1

µF

0.1

µF

0.1

µF

SHDN

NOTE A: The enable terminal can be tied to a generall purpose I/O terminal on the PCMCIA controller or tied high.

Figure 33. TPS2205 with TPS6734 12-V, 120-mA Supply