参数资料
型号: TSM101AIDT
厂商: STMICROELECTRONICS
元件分类: 模拟信号调理
英文描述: SPECIALTY ANALOG CIRCUIT, PDSO8
封装: MICRO, PLASTIC, SO-8
文件页数: 9/13页
文件大小: 387K
代理商: TSM101AIDT
5/13
This technical note shows how to use the TSM101
integrated circuit with a switching mode power
supply (SMPS) to realize a battery charger.
An example of realization of a 12V Nickel-cadmi-
um battery charger is given.
1 - TSM101 PRESENTATION
The TSM101 integrated circuit incorporates a high
stability series band gap voltage reference, two
ORed operational amplifiers and a current source
(Figure 1)
Figure 1 : TSM101 Schematic Diagram
This IC compares the DC voltage and the current
level at the output of a switching power supply to
an internal reference.It provides a feedback
through an optocoupler to the PWM controller IC
in the primary side.
The controlled current generator can be used to
modify the level of current limitation by offsetting
the information coming from the current sensing
resistor.
A great majority of low or medium end power sup-
plies is voltage regulated by using shunt program-
mable voltage references like the TL431
(Figure 2).
The galvanic insulation of the control information
is done by using an opto-coupler in linear mode
with a variable photo current depending on the dif-
ference between the actual output voltage and the
desired one.
A current limitation is used to protect the power
supply against short circuits, but lacks precision.
This limitation is generally realized by sensing the
current of the power transistor, in the primary side
of the SMPS.
The role of the TSM101 is to make a fine regula-
tion of the output current of the SMPS and a pre-
cise voltage limitation.
The primary current limitation is conserved and
acts as a security for a fail-safe operation if a
short-circuit occurs at the output of the charger.
2 - PRINCIPLE OF OPERATION
The current regulation loop and the voltage limita-
tion loop use an internal 1.24V band-gap voltage
reference. This voltage reference has a good pre-
cision (better than 1.5%) and exhibits a very stable
temperature behavior.
The current limitation is performed by sensing the
voltage across the low ohmic value resistor R5
and comparing it to a fixed value set by the bridge
composed by R2 and R3 (Figure 3).
When the voltage on R5 is higher than the voltage
on R3 the output of the current loop operational
amplifier decreases. The optocoupler current in-
creases and tends to reduce the output voltage by
the way of the PWM controller.
The voltage regulation is done by comparing a
part of the output voltage (resistor bridge R6, R7
and P1) to the voltage reference (1.24V).
If this part is higher than 1.24V, the output of the
voltage loop operational amplifier decreases.
1
2
3
4
8
5
6
7
Vref
APPLICATION NOTE
A BATTERY CHARGER USING THE TSM101
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相关代理商/技术参数
参数描述
TSM101AIN 制造商:未知厂家 制造商全称:未知厂家 功能描述:Power Control/Management
TSM101AIP 制造商:未知厂家 制造商全称:未知厂家 功能描述:Analog IC
TSM101AN 制造商:未知厂家 制造商全称:未知厂家 功能描述:Analog IC
TSM101C 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:VOLTAGE AND CURRENT CONTROLLER
TSM101C-AC 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:VOLTAGE AND CURRENT CONTROLLER