STEVAL-ISA020V1 STMicroelectronics, STEVAL-ISA020V1 Datasheet - Page 6

• Manufacturer Part Number: STEVAL-ISA020V1
• Description: EVAL BOARD 3.5W BATTERY CHARGER
• Manufacturer: STMicroelectronics
• Type: Battery Managementr

Specifications of STEVAL-ISA020V1

• Design Resources: STEVAL-ISA020V1 Gerber Files Battery Charger with TSM101 Bill of Material
• Main Purpose: Power Management, Battery Charger
• Embedded: No
• Utilized Ic / Part: VIPer12AS, TSM101
• Primary Attributes: 3.5W, 0 ~ 7 V @ 500mA Out, Off-Line
• Secondary Attributes: 88 ~ 264 VAC
• Input Voltage: 88 V to 264 V
• Output Voltage: 0 V to 7 V
• Product: Power Management Modules
• Silicon Manufacturer: ST Micro
• Silicon Core Number: VIPer12AS-E And TSM101
• Kit Application Type: Power Management
• Application Sub Type: SMPS
• Kit Contents: Board
• Rohs Compliant: No
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: VIPer12AS-E, TSM101
• Other names: 497-5519

TSM101/A
6/13
Figure 2 : SMPS Using a TL431 as Voltage Controller
The optocoupler current increases and tends to
reduce the output voltage by the way of the PWM
controller.
By enabling the TSM101 current source (pin 2) it
is possible to offset the current sensing by a volt-
age equal to :
Voff # R4 * Io with I
This offset lowers the output charge current and
this function can be used to charge two types of
batteries having different capacities. The current
source is enabled by connecting pin 2 to ground
3 - CALCULATION OF THE ELEMENTS
The charge current is regulated at 700mA (if the
charge control input is left open) or 200mA (if the
charge control input is put to ground ), allowing the
charge of two different types of batteries.
3.1 - Voltage limitation
The end-of- charge voltage is limited at 1.45V/cell,
this is the recommended voltage for an ambient
temperature at 25oC.
A diode is generally inserted at the output of the
charger to avoid the discharge of the battery if the
charger is not powered. This diode is sometimes
directly integrated in the battery pack. The influ-
ence of this diode on the charge is negligible if the
voltage drop (0.7V) is taken into account during
the design of the charger.
The voltage at the output of the charger is :
and regarding R6 and R7 :
V
out
=
R6
----------------------
R6
+
R 7
o
V
r
= 1.4mA
P1, which is a part of R6 and R7 is not considered
in this equation.
The following values are used on the application
board :
battery replaced by a 1k resistor
3.2 - Current regulation
R5 is the sense resistor used for current measure-
ment.
The current regulation is effective when the volt-
age drop across R5 is equal to the voltage on pin
5 of the TSM101 (assuming that the internal cur-
rent source is disabled).
For medium currents (<1A), a voltage drop across
R5 of 200mV = Vr5 is a good value, R5 can be re-
alized with standard low cost 0.5W resistors in
parallel.
parallel)
R2 and R3 can be chosen using the following for-
mula :
CHARGE CONTROL
If the pin 2 is left open, the charge current is nom-
inal at # 700mA.
R6=
R7 = 12k
R6 = 1k
R10 = short circuit
C3 = 100nF
R2 =
R5 =
P1 = 220 , adjust for V
R3
------------------------------- -
Vout Vref
Vr5
--------- -
Ich
Vref
, R5 = 0.285
–
Vref Vr5
--------------------------- -
V r5
–
R7
output
(four 1.2
= 15.2V with the
resistor in