Datasheet

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     
   
SLVS282B − SEPTEMBER 2000 − REVISED JULY 2005
16
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APPLICATION INFORMATION
TPS2211A control logic
AVPP
CONTROL SIGNALS INTERNAL SWITCH SETTINGS OUTPUT
SHDN VPPD0 VPPD1 S4 S5 S6 AVPP
1 0 0 CLOSED OPEN OPEN 0 V
1 0 1 OPEN CLOSED OPEN AVCC
†
1 1 0 OPEN OPEN CLOSED VPP (12 V)
1 1 1 OPEN OPEN OPEN Hi-Z
0 X X OPEN OPEN OPEN Hi-Z
†
Output depends on AVCC
AVCC
CONTROL SIGNALS INTERNAL SWITCH SETTINGS OUTPUT
SHDN VCCD1 VCCD0 S1 S2 S3 AVCC
1 0 0 CLOSED OPEN OPEN 0 V
1 0 1 OPEN CLOSED OPEN 3.3 V
1 1 0 OPEN OPEN CLOSED 5 V
1 1 1 CLOSED OPEN OPEN 0 V
0 X X OPEN OPEN OPEN Hi-Z
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
capacitor, and a small capacitor for loop compensation. The entire converter occupies less than 0.7 in
2
of PCB
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).