TSM101A STMicroelectronics, TSM101A Datasheet - Page 12

• Manufacturer Part Number: TSM101A
• Description: VOLTAGE AND CURRENT CONTROLLER
• Manufacturer: STMicroelectronics

TSM101/A
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 chosenfollow-
ing equation 2 :
The total value of the resistor bridge should be in
the range of the k
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 :
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
resistor R4.
If Ilim1 is the current limit calculated in the previous
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 :
where Isce = 1.4mA
C4 and C5 are bypass capacitors used to
smoothen the regulated outputs.
C2 and C3 are capacitors used for high frequency
compensation.
EXAMPLES OF COMPONENT LISTS
Table 1 summerizes a few examples of component
lists to generate quickly 15V/700mA/20 0mA,
12V/1A/500mAor 8.2V/200mA/100mAvoltage and
current regulations.
12/15
Vsense = R3/(R2+R3)xVref
Ilim = Vsense/R5
R4 = (Vsense - Ilim2xR5)/Isce
in order to ensure a proper
eq2
eq3
eq4
Table 1
Figure 2 represents in real dimensions thePCB and
the silkscreen of the TSM101 Evaluation board.
Figure 2
R1
R2
R3
R4
R5
R6
R7
P1
2 straps
C2
C3
C4
C5
Voltage /
Current
Control
700mA
200mA
1.2 x4
100nF
100nF
100nF
1.2k
10k
220
100
12k
100
10 F
15V
1k
0
500mA
0.8 x4
100nF
100nF
100nF
1.2k
8.2k
220
100
10k
22 F
68
12V
1k
1A
0
200mA
100mA
100nF
100nF
100nF
1.2k
5.6k
220
100
4.7 F
10k
1 x1
8.2V
68
1k
0