(under construction)

Description:

Testing of circuits that involve charging and discharging of batteries requires some special power supplies. Regular power supplies can only source power, and don't respond when the voltage on the output gets above the setpoint, or they can even get damaged. For the purpose of sinking energy, a electric load can be added. However, that requires some delicate programming of supply and load voltages to prevent current flow between those devices. Alternatively, a real two-quadrant power supply can be used. In either case, there is some fairly expensive instrumentation involved. When testing battery management boards for multiple cells, then the cost for such test will increase rapidly. In addition, it means a significant amount of effort to put the test system together each time it is to be used.

By having a small two-quadrant regulator module, the construction of such test jig can be simplified significantly. In addition, the cost is low enough to integrate these regulators inside the testing jig.

Application:

This emulator is used for the functional board test of the Off-Grid Battery controller. This module contains an LTC3300 based 8-cell active balancer capable of 10A cell (dis)charge currents. Using these two-quadrant cell emulators, we do not have to dissipate lots of energy during the testing. Instead, the power supply for the test system merely provides the energy that is lost due to efficiency of the emulators and the balancers under test.

Specifications:

• Output voltage 2.5V-4.5V
• Output current ±10A max
• Isolation 500V
• Input voltage 22-40V
• Analog output voltage control
• Output voltage and current monitoring via I²C
• Up to 16 emulators on one I²C bus (referenced to input ground)

References:

The design of this cell emulator is based on the article "Build an electronic battery simulator" in EDN written by Jon Munson, Applications Engineer at Linear Technology.