Getting Started With the TAA3033DB1649 Automotive Demo Board for Precharge Application

2.1 Getting to Know the Hardware

TAA3033DB1649 Features

• Buck converter for precharge function of DC-link capacitor
• Designed for low-side
• applications
• Features automotive-qualified components
• Uses an Automotive-grade inductor with a low inductance value of 70 uH
• Input: 800 V/5 A
• Supports both 400 V and 800 V electric vehicle (EV) battery systems
• Charges a 1 mF capacitor to 400 V in 120 ms and to 800 V in 260 ms
• Optional I²C communication for programming and/or monitoring the status signals from the TAA3033AT

Specifications

Table 1. Specifications.

2.2 Ringo Development Software with GUI

The TAA3033 Ringo software with GUI enables communication with the integrated circuit (IC) using a PC and the RDK01DB1563 USB-to-inter-integrated circuit (USB-to-I²C) interface kit. When used with the demo board, the Ringo GUI supports development and evaluation. The tool enables:

• Reading the parameter settings and status signals from the IC
• Configuring adjustable parameters
• Adapting protection settings to match application requirements

Refer to UM12429 for detailed information on GUI setup, features and operation.

2.3 Demo Board Safety Guidelines

• Ensure that the DC-link capacitor and the input filter capacitor are fully discharged after every operation
• This board does not include a measurement point, indicator or display for the voltage across the connected capacitor. After operation, the capacitor may remain charged to hazardous voltage levels
• Before handling the board, connected wiring or the capacitor:
  • Ensure that the DC input supply is disconnected
  • Ensure that the input filter capacitor (C7) and the DC-link capacitor are discharged
  • Verify the capacitor voltage using externally arranged high-voltage measurement equipment with an appropriate rating
  • Discharge the capacitor using a suitably arranged discharge circuit or method
  • Ensure that all external components, including discharge circuits, measurement probes, connectors and cables, have insulation ratings appropriate for the maximum operating voltage
  • Verify capacitor discharge before handling the board because the demo board does not detect, measure or indicate whether the capacitor has been discharged

3.1 Test Setup and Equipment

To demonstrate the performance of the TAA3033DB1649 demo board, a test setup is used to charge a 1 mF capacitor to 800 V.

The test equipment includes:

• Oscilloscope: Yokogawa DLM5038
• High-voltage direct current (HVDC) power source: ITECH bidirectional DC source IT-M3906C-1500-12
• DC power supply: E36312A programmable DC power supply
• DC-link capacitor: Polypropylene, 1000 μF, 900 V, 10 %

Figure 4 shows the test setup using the demo board. To avoid reverse current flow during evaluation, an external diode is added in series between the positive terminal of the high-voltage direct current (HVDC) power supply and the BAT+ terminal of the demo board. An external fuse is also added in series with the diode. For accurate measurement with minimal disturbance to the application, the sense signal must be measured close to the IC (see Figure 5).

As shown in Figure 5, a 1:1 probe is connected directly across capacitor C3 to measure the SNC signal. A differential probe is used to measure the capacitor voltage (VCAP). Several test points are provided on the demo board to facilitate the measurement of signals such as Enable, Fault, Ready, Vcc, switching node voltage, Gate. The board also includes a solder-blob jumper, which is shorted by default. The solder bridge may be opened and an external wire loop attached for inductor current measurement.

TAA3033DB1649

TAA3033DB1649

Figure 5. SNC Signal Measurement.

3.2 Test Procedure

The test procedure for evaluating the demo board is given in this section. The same test procedure can be followed for the evaluation of both TAA3033DB1649 and TAA3033DB1650 demo boards.

If the IC is already programmed with the required settings, the following steps can be followed:

1. VCC voltage (24 V; 1 A) is turned on
2. DC voltage of 800 V or 400 V is turned on
3. ENA pin is pulled high to 5 V to start precharging
4. At the end of precharging, the DC source is turned off and disconnected. The ENA pin is pulled low and the capacitor is discharged

To evaluate the precharge operation with other configurable settings, the following procedure can be used:

1. VCC voltage (24 V; 1 A) is turned on
2. RDY pin is pulled high to 5 V
3. ENA pin is pulled high to 5 V
4. The Ringo GUI is used to program the IC with the desired settings
5. DC voltage of 800 V or 400 V is turned on
6. RDY pin is pulled low to start precharging
7. At the end of precharging, the DC source is turned off and disconnected. The ENA pin is pulled low and the capacitor is discharged

3.3 Startup Behavior

When the applied VCC voltage exceeds the start voltage level and the voltage at the enable pin exceeds the enable threshold, the IC operation starts (see Table 1). Figure 6 shows the startup behavior with zero battery voltage.

The oscilloscope channels are assigned as follows:

1. Channel 1 (CH1): Enable (ENA)
2. Channel 2 (CH2): Ready (RDY)
3. Channel 3 (CH3): Fault (FLTN)
4. Channel 5 (CH5): Gate (GATE)

When the voltage at the enable pin exceeds the threshold voltage, the fault pin goes high and gate switching starts. Gate switching starts with a minimum duty cycle and then increases. The ready pin remains low until the end of the precharging operation.

Figure 6. Startup Behavior.

3.4 Precharge Operation

Figure 7 and Figure 8 shows the precharge operation to 400 V and 800 V, respectively, with the DB1649 demo board. The oscilloscope channels are assigned as follows:

1. Channel 1 (CH1): Enable (ENA)
2. Channel 2 (CH2): Ready (RDY)
3. Channel 3 (CH3): Fault (FLTN)
4. Channel 4 (CH4): Inductor current (IL)
5. Channel 5 (CH5): Gate signal (GATE)
6. Channel 6 (CH6): Capacitor voltage (VCAP)
7. Channel 7 (CH7): Switching node signal (SW)
8. Channel 8 (CH8): Battery voltage (VBAT)

Figure 7. Precharge Operation at 400 V.

Figure 8. Precharge Operation at 800 V.

Board Information

• UM12428, TAA3033DB1649 Automotive Demo Board for Precharge Application
• Ringo TAA3033 Development Software with GUI User Manual
• TAA3033DB1649 Design Files
• Active Precharge Controller Design Tool for TAA3033

Software

• Ringo TAA3033 Software