ISSUE 2 - JANUARY 2000
ZDS1009
SM-8 COMPLEMENTARY CURRENT MIRROR
1
FEATURES
"   Excellent Temperature Tracking Characteristics
"   Compact Cost Effective Solution
"   Simplifies Circuit Implementation
"   Broad application base from
Single Cell Li-ion High Side Current sense chargers to
Multi-cell Lead-Acid systems
"   Only 4 Connections required
DESCRIPTION
The  ZDS1009  current  mirror  has  been  developed
specifically  for  high  side,  current  sense  plus  level
translation applications and as such will find a broad
applications  base  including  battery  charge
management,  DC  motor  control  and  over  current
monitoring  functions.  It  is  of  particular  interest  for
current sense applications for feedback purposes in fast
battery chargers for Li-Ion cell based systems.
Thedevicefunctionsbysensingthevoltagedeveloped
across an external (user defined) high side current
sense  resistor,  and  by  an  arrangement  of  current
mirrors refer this sensed voltage, with or without
multiplication, to a low side referenced signal. This
signal can then be used, for example, to close the
control loop to a  controller IC, for a DC-DC converter
providing charge to a battery.
TYPICAL APPLICATION CIRCUIT
V
IR
R
R
sense
2
4
1
=
For balance R3=R4
eg
R2=100m&
R1=R3=R4=100&
V
sense
sensitivity = 100mV/A
SM-8
(8 LEAD SOT223)
SCHEMATIC DIAGRAM
CONNECTION DIAGRAM