Other Parts Discussed in Thread: TPS54320, TPS543620, TPS543320, OPA544
We are currently planning to design a PCB test fixture for a circuit board that has BQ24104 charging circuit section on it. We would like to come up with a way of verifying/validating the charging circuit on board. This is for production testing. We aim to have the test circuit be integrated on the design test fixture PCB. This means we cannot use an actual 4 quadrant power supply equipment as well as an actual electronic load equipment. Using an actual battery is also out of the question. We wanted to verify from TI some solutions we are thinking of for testing the charging circuit and also ask if TI also has a solution/reference design for testing charging circuits without the need to use a power supply/electronic load.
Our design has BQ24104 configured to charge a 2S4P Battery Pack. We have configured the circuit to charge at 2A. Our ideal goal is to be able to verify that the pre-charge, fast charge and charge termination of BQ24104 circuit works. We can also limit the scope to just verifying fast charging if that would make the battery simulator/ charger tester design simpler. Can we assume that if the fast charging part of the BQ24104 is functional, that the other modes (pre-charge and charge termination) is functional as well? What is the probability of the other modes working if the fast charge part is working?
Below are out solutions that we want to verify from TI if it would work to test BQ24104 and have some questions if TI has solutions for specific circuit designs
1. The Link below is a question regarding testing battery fuel gauge using a resistors and a voltage across the test circuit terminals (B+/B-). Can this circuit (resistor with voltage applied across it) be used to simulate a battery to test the charging circuit? Instead of using an actual power supply, we would be using a variable output buck converter to change the voltage and simulate the different levels of the battery capacity?
2. Can we use a DCDC converter (buck) with sink capability to as battery simulator? The link below suggested to use TPS54320. The current recommended part replacement for TPS54320 is TPS543320. We are thinking of using TPS543620 since is has a higher sink current limit. This post was from 10 years ago so we would want to verify if this design has been verified and will work in testing the battery charger.
3. Battery Simulator Reference Designs. When searching TI application notes regarding battery simulation, there were 2 notes that showed up immediately in a google search result.
https://www.ti.com/lit/an/slua999/slua999.pdf - A Simple Battery Simulator
https://www.ti.com/lit/an/slva618/slva618.pdf - Building Your Own Battery Simulator
SLVA618 abstract mentions that this power amplifier circuit test single-cell Li-ion battery chargers. Can this circuit be used to test 2S battery chargers? Are there modifications to the circuit that needs to be done in order to test 2S chargers? Or is it trying to find the appropriate voltage across VIN+ and VIN- to get a voltages of a 2S Battery?
For the SLUA999 application note, it can be configured for multi-cell simulation but the note only mentions about testing fuel gauges. Can this be use to test battery charger circuits? Are there circuit design modifications needed to be done to meet the criteria?
Does TI have development boards, schematic/layout reference design for the two application notes mentioned above?
4. Reference design for a 4 quadrant power supply, electronic load with CV mode or source meter
Since we do not want to use an actual equipment to test the battery charger, does TI have a reference design for a simplified version of the test and measurement mentioned above?
Power Supply with sinking capability?
Electronic Load with CV Mode?
Let us know if any of these solutions would work?
The order of solutions listed above is listed from simple to complex from our perspective.