STEVAL-ISA020V1 STMicroelectronics, STEVAL-ISA020V1 Datasheet - Page 9

• 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

VIPER12A-E
6
Feedback pin principle of operation
A feedback pin controls the operation of the device. Unlike conventional PWM control
circuits which use a voltage input (the inverted input of an operational amplifier), the FB pin
is sensitive to current.
Figure 5.
The power MOSFET delivers a sense current I
R2 receives this current and the current coming from the FB pin. The voltage across R2 is
then compared to a fixed reference voltage of about 0.23 V. The MOSFET is switched off
when the following equation is reached:
By extracting I
Using the current sense ratio of the MOSFET G
Internal current control structure
S
:
Figure 5.
I
Doc ID 11977 Rev 2
D
presents the internal current mode structure.
=
R
G
2
ID
⋅
(
I
I
⋅
S
S
I
S
+
=
I
=
FB
0.23V
--------------- - I
R
G
)
2
ID
s
=
ID
which is proportional to the main current Id.
⋅
0.23V
–
⎛
⎝
:
0.23V
--------------- - I
FB
R
Feedback pin principle of operation
2
–
FB
⎞
⎠
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