MLX83202 Datasheet, PDF (25/35 Pages) Melexis Microelectronic Systems – Automotive NFET pre-drivers

MLX83202/MLX83203
Automotive NFET pre-drivers
8.6 Current sense amplifier
The sense amplifier offers low input offset, and fast settling times. Its input range can be adjusted by applying
a suitable voltage on the VREF pin, typically as a resistor divider from VDD to GND. For the definition of
VREF, the input offset, the current range, and the linear output range of the ISENSE pin should all be taken
into account.
For input signal:
Vin = Visp - Visn,
Max input offset:
Voffsetmax = Vis_iomax + Trange * Vis_io_tdrift
(over full temperature range =Trange)
Visense = (Vin +/-Voffset)*IS_Gain + VREF has to be in the range [V_ISENSEmin, V_ISENSEmax]
 Imin = [ (Visensemin – VREF) / IS_GAIN + Voffset ] / Rshunt
 Imax = [ (Visensemax – VREF) / IS_GAIN - Voffset ] / Rshunt
Input offset voltage
Input offset voltage thermal drift
Closed loop gain
ISENSE Output voltage range HIGH
ISENSE Output voltage range LOW
Vis_io
Vis_io_tdrift
IS_GAIN
V_ISENSEmax
V_ISENSEmin
The below table shows the current input range (Amp) for two resistive divider settings on VREF:
1) VREF = VDD/2 for a symmetrical input range
2) VREF = VDD/18 for a maximum current level, while ensuring it is possible to measure the input
offset before starting the motor (Isense_min > 0A).
Remark: for ease of calculation a max temperature offset drift of 1mV was added to the 5mV offset
=> max input offset = 6mV
VDD
Visensemin
Visensemax
div
VREF
3.3
3.3
3(**)
3(**)
5
5 4.5(**)
4.5(**)
0.02
0.02
0.02
0.02
0.02
0.02
0.02
0.02
3.28
3.28
2.98
2.98
4.98
4.98
4.48
4.48
2
18
2
18
2
18
2
18
1.65
0.18
1.50
0.17
2.50
0.28
2.25
0.25
3901083203
Rev 2.2
Page 25 of 35
Prelim. Data Sheet
4 Dec 2013