RC

filter

BOOST

OSCILLATOR

SYNC

FB

OFF/BLANK

TIME

PULSE

GENERATOR

CURRENT

RAMP

GENERATOR

BLANK

TIME

SW

OVP

S

OCP

LIGHT

LOAD

R

R

R

R

-

+

FSET

CTRL

ADAPTIVE

VOLTAGE

CONTROL

D

CURRENT

SENSE

PGND

R1

R2

TPS61193-Q1

www.ti.com

SNVSAC7 – OCTOBER 2015

Feature Description (continued)

Figure 8. Boost Block Diagram

DC-DC can be driven by an external SYNC signal between 300 kHz and 2.2 MHz. If the external synchronization

frequency disappears and SYNC pin level is low, converter continues operation without spread spectrum

immediately. If SYNC remains high, converter continues switching with spread spectrum enabled after 256 µs.

The optional spread spectrum feature (±3% from central frequency, 1-kHz modulation frequency) reduces EMI

noise at the switching frequency and its harmonic frequencies. When external synchronization is used, spread

spectrum is not available.

Table 1. DC-DC Synchronization Mode

SYNC PIN INPUT

MODE

Low

Spread spectrum disabled

High

Spread spectrum enabled

300 to 2200 kHz frequency

Spread spectrum disabled, external synchronization mode

TYPICAL BOOST

FREQUENCY

TYPICAL

INPUT

MINIMUM SWITCH

BLANK

CURRENT

CURRENT RAMP

RANGE

(kHz)

INDUCTANCE (µH)

AND OUTPUT

OFF TIME (ns)

(2)

TIME (ns)

RAMP (A/s)

DELAY (ns)

CAPACITORS (µF)

1

300...480

33

2x10(cer.)+33(electr.)

150

95

24

550

2

480...1150

15

10(cer.)+33(electr.)

60

95

43

300

3

1150...1650

10

3x10(cer.)

40

95

79

0

4

1650...2200

4.7

3x10(cer.)

40

70

145

0

(1)

Parameters are for reference only

(2)

Due to current sensing comparator delay the actual minimum off time is 6 ns (typical) longer than in the table.

Copyright © 2015, Texas Instruments Incorporated

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