TD230 datasheet(9/15 Pages) STMICROELECTRONICS

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Figure 6 :

Step Up Converter Rise Time

Proper operation of this step-up converter is guar-

anteed at as low as 2.7V with a rise time (0 to 90%

of V(CBOOST)) in the range of 700

µs at 2.7V which

Vcc+

GND

LBOOS T

CTRIP1

CBOOS T

C ONTR OL

P Vcc

LBOOS T

CBO OS T

PM1

GND

PM2

OS C GND

NVcc

REF1

GC 1

S ENS P

INHIBIT

S HUTDOWN

S ENS N

GC 2

REF2

RS 1

NMos

to BOARD

CS S 1

Figure 7 :

Single Electronic Circuit Breaker

Application

is the worst case. At 5V, the rise time of V(Cboost)

is 250

µs typ. The CBOOST voltage wave form at

power ON under 5V supply voltage is shown on

figure 6.

Trace 1 represents the power supply voltage (0 to

5V).

Trace 2 represents the CBOOST Voltage at power

ON (0 to 5+13,4 = 18,4V).

Table (a) summerizes the recommended values of

the CBOOST and LBOOST to ensure optimized gate

charge and low ripple voltage with their corre-

sponding maximum current surge (IPK) and nomi-

nal consumption (ICC) of the TD230 for the most

common power supply values. For each power

supply value is also given the recommended value

of a bypass capacitor (CBY) on the power sup-

plies.

Note that both CBOOST and LBOOST are available in

surface mount packages.

Table (a) : Recommended values for Cboost and

Lboost

VCC

Cboost

Lboost

Ipk

Vrip

Icc

Cby

VnF

µHmA

µF

2.7

100

190

100

5>1

100

220

120

2.5

100

220

470

220

100

2.2

220

470

150

2.2

220

680

150

2.4

220

1000

200

2.7

2.4. Single Supply Breaker Application

The TD230 is perfectly suited to fit in single sup-

plied applications (ex 0-5V), and can drive only one

power MOSFET used as high side power switch.

Figure 7 shows how TD230 can be used as a

single circuit breaker with the same performances.

In this case, the external components consist in :

one boost inductor, one sense resistor, three ca-

pacitors, and one power MOSFET.

2.5. Typical Telecom Line Cards Protection

Application

One of the typical applications where the TD230

can display all its technical advantages is in an

exchange Telecom Cards protection. Sometimes

fifty cards or more are to be supplied with the same

power supply (+/-5V, 1kW), and a decentralized

protection is needed because one card may be

faulty, but should not penalize the others with un-

adapted protection system. The risk of complete

breakdown of the system must be eradicated.

In this application the two above described over

current causes (external line perturbation or inter-

nal component fault) are likely to happen. In the first

case, the current limitation on each card will ensure

undammagingon-board conditions, and in the sec-

ond case, the faulty card will be disjoncted from the

power supply until reset.

Figure 8 shows a typical telecom application with

decentralized protection.

In this application, the positive power supply serves

the logic control and analog signals whereas the

negative power supply is dedicated to the analog.

TD230

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