TSM101 datasheet(11/13 Pages) STMICROELECTRONICS

11 / 13 page

TSM101/A

11/13

The current control is given by the choice of the

voltage drop through the sense resistor R5 (to be

linked to the nominal current of the application)

and by the value of the sense resistor itself.

For medium currents (< 1A), a good value for the

voltage drop through R5 can be Vsense = 200mV

(dissipation < 200mW).

The resistor bridge R2/R3 should be chosen fol-

lowing equation 2 :

• Vsense = R3/(R2+R3)xVref

eq2

The total value of the resistor bridge should be in

the range of the kW in order to ensure a proper

charge for the voltage reference (in the range of

the mA).

To set the current limit, the sense resistor R5

should be chosen following equation 3 :

• Ilim = Vsense/R5

eq3

The internal current generator (Isce) can be used

to offset the current limitation with a lower value.

This current generator is activated by connecting

pin 2 to ground. It is inhibited if pin 2 is connected

to the positive rail via the pull up resistor R1.

The current offset is given by the choice of the re-

sistor R4.

If Ilim1 is the current limit calculated in the previ-

ous paragraph, and Ilim2 is the current limit that is

to be set when pin 2 is connected to ground, R4

should be chosen following equation 4 :

• R4 = (Vsense - Ilim2xR5)/Isce

eq4

where Isce = 1.4mA

C4 and C5 are bypass capacitors used to smooth-

en the regulated outputs.

C2 and C3 are capacitors used for high frequency

compensation.

EXAMPLES OF COMPONENT LISTS

Table 1 summerizes a few examples of compo-

nent lists to generate quickly 15V/700mA/200mA,

12V/1A/500mA or 8.2V/200mA/100mA voltage

and current regulations.

Figure 2

Voltage/

Current

Control

15V

700mA

200mA

12V

500mA

8.2V

200mA

100mA

10k

Ω

10k

Ω

10k

Ω

1.2k

Ω

1.2k

Ω

1.2k

Ω

220k

Ω

220k

Ω

220k

Ω

100

Ω

1.2

Ω x 4

0.8

Ω x 4

Ω x 1

Ω

12k

Ω

8.2k

Ω

5.6k

Ω

100

Ω

100

Ω

100

Ω

2 straps

Ω

100nF

µF22µF4.7µF

100nF

TSM101 Datenblatt(PDF) 11 Page - STMicroelectronics

TSM101 Datenblatt(HTML) 11 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13

Datenblatt Download

Link URL