MAX1757EVKIT Maxim Integrated, MAX1757EVKIT Datasheet - Page 2

• Manufacturer Part Number: MAX1757EVKIT
• Description: Battery Management Evaluation Kit for the MAX1757 MAX1758
• Manufacturer: Maxim Integrated
• Series: MAX1757r

Specifications of MAX1757EVKIT

• Battery Type: Li-Ion, Li-Poly
• Operating Supply Voltage: 6 V to 14 V
• Charge Safety Timers: Yes
• Operating Supply Current: 5 mA
• Product Type: Charge Management
• Temperature Monitoring: Yes
• Uvlo Start Threshold: 2.4 V
• Uvlo Stop Threshold: 2.6 V

The MAX1757/MAX1758 EV kits are fully assembled
and tested surface-mount boards. Follow the steps
below to verify board operation. Do not turn on the
power supply until all connections are completed.
Observe all precautions on the battery manufactur-
er’s data sheet. Use only lithium-ion (Li+) cells with
this charger:
1) Set jumper JU3 to indicate the number of cells in the
2) Place a shunt on jumper JU1 to disable the tempera-
3) Place a shunt across pins 1–2 on JU2 to enable the
4) For the MAX1757, connect a +7VDC to +14VDC
5) Connect a lithium-ion (Li+) battery pack between the
6) Turn on the power supply.
7) Verify that LEDs 1, 2, and 3 indicate the correct
When battery charging is initiated, the charger enters
the prequalification state. In this state, the batteries are
charged at 1/10 of the programmed current limit while
the charger measures the battery to determine if it can
be charged. If the battery voltage is above 2.5V per
cell, charging begins. At this time, the batteries are
charged at a constant current (fast-charge state) or a
constant voltage (full-charge state). The charger exits
the full-charge state and enters the top-off state once
the battery current drops to 10% of the fast-charge cur-
rent, or the fast-charge timer expires. The charger
remains in the top-off state for 45 minutes, after which
charging is terminated.
Once charging is terminated, if the battery voltage
drops 5% from the fully charged voltage, charging
automatically restarts.
If at any time during charging, the thermistor input
senses a temperature below 0°C or above +50°C,
charging suspends until the temperature returns to a
safe level. This kit is shipped with a 10kΩ resistor to
disable the temperature monitoring function. If temper-
ature monitoring is required, connect the appropriate
MAX1757/MAX1758 Evaluation Kits
2
battery pack (Table 1).
ture monitoring functions.
MAX1757 or MAX1758.
power supply with sufficient power rating across the
VIN and GND pads.
For the MAX1758, connect a +7VDC to +28VDC
power supply with sufficient power rating across the
VIN and GND pads.
BATT+ and BATT- pads.
charging status.
_______________________________________________________________________________________
Detailed Description
Quick Start
thermistor (see Jumper Selection section).
If the charger is unable to enter the fast-charge or full-
charge states, charging is terminated and the fault LED
(red) lights to indicate a faulty battery.
For more information on the operation of the MAX1757
or MAX1758, refer to the Detailed Description sections
of the MAX1757 and MAX1758 data sheets.
The three LEDs on the EV kit indicate the charging status:
o LED1 (FULL) indicates that the battery pack is being
o LED2 (FAST) indicates that the battery pack is being
o LED3 (FAULT) indicates that charging terminated ab-
The voltage at the ISETOUT pin sets the charging cur-
rent to the battery. The MAX1757/MAX1758 EV kits are
shipped with ISETOUT connected to REF. This sets the
charging current to the full-scale value of 1.5A.
To change the charging current to a lower value, cut
the trace shorting the two pads of R3 and install resis-
tors for R3 and R4. Use the equations below to calcu-
late the resistor values:
Use 100kΩ for R4.
The input current limit is set by sense resistor R1 and
by the voltage applied to the ISETIN pin. This sets the
input current limit to 2A (100mV/50mΩ). The
MAX1757/MAX1758 EV kits are shipped with ISETIN
connected to REF and a 50mΩ sense resistor.
To change the input current limit to a lower value, cut
the trace shorting the two pads of R5 and install resis-
tors for R5 and R6. Use the equations below to calcu-
late the resistor values:
Use 100kΩ for R6.
To further increase the input current limit, reduce the
value of sense resistor R1.
charged with a constant voltage.
charged with a constant current.
normally.
I
CHG
R3 = ((1.5A / I
I
IN
R5 = ((2A / I
= (R6 / (R5 + R6)) x 2A
= (R4 / (R3 + R4)) x 1.5A
CHG
IN
) - 1) x R6
) - 1) x R4
Charging Current
Charging Status
Input Current