TIDA-01168: Operation of TIDA-01168 converter

Hello ksma, 

thank you for the interest in the TIDA-01168. I am the author of the design and happy to assist you. Would you be able to share the circuit diagram with me? The loading effect actually indicates a series resistance about 0.184 ohm per phase (0.046 x 4 or 0.092 x 2).

Where exactly do you measure the output voltage? You need to measure the output voltage exactly at the point where the 4-wire voltage sensing is. The voltage drop on wires can cause such a voltage drop. 

Could you please also check if the output of the voltage sensing amplifier remains same or changes when you go from 5 to 50 Amps?

Let me also think about the source code. It has been a while since I worked on the TIDA-01168. I need to refresh it a bit.

Best regards, Jiri

Hello, Jiri-san.

Thank you for your reply.

I'm sorry, but I can't present a schematic.

However, it is almost the same as the reference circuit diagram. The change is that the number of smoothing capacitors has been slightly reduced.

The voltage measurement point is the same.

The voltage amplifier output (P12V_MEAS) also decreases with the load current.

In subsequent studies, if Bn and An were lowered, the voltage drop further increased.

Example) 14.03V / 0A, 12.78V / 20A, 10.96V / 50A

However, if raised in reverse, the ISETD signal becomes unstable.

Is this a lack of tuning for 2P2Z?

Based on the #define of control.h, it is confirmed by moving up and down a little.

/ * Buck mode digital compensation constants * /

#define B0_BUCK (2.602812) // (0.443017) / * B0 constant * /

#define B1_BUCK (0.040566) // (0.264689) / * B1 constant * /

#define B2_BUCK (-2.562246) // (-0.17832) / * B2 constant * /

#define A1_BUCK (0.918233) // (0.466008) / * A1 constant * /

#define A2_BUCK (0.081767) // (0.533991) / * A2 constant * /

Can TIDA-01168 be driven by the above parameters?

Thanks and best regards,ksma

Hello,Jiri,

Thank you for your reply.

Thank you for useful technical material.
I read it before and was very helpful.

But the question remains.
(1) Removed only one 39u / 63V polymer capacitor.
For this reason, changes in the transfer characteristics of the plant are considered to be small.

(2) Inadequate tuning of the controller can cause output voltage pulsation or
I think it will affect the transient response.
However, this time the output voltage drops statically.

(3) The voltage drop rate varies slightly depending on the tuning of Bn and An.
However, it will not improve at all.

In tuning TIDA-01168,
Was there such a phenomenon?

I would appreciate it if you could tell me about the development status at that time.

Best regards,ksma

Hello Ksma, 

(un)fortunately, I have not seen this behavior when designing the TIDA-01168. This makes it extremely difficult for me to help you with debugging the system.

I would focus to the digital compensator. I suggest you create a plot where

• The X axis is the output current
• The Y axis has following parameters:
  • Duty cycle of the ISETD signal
  • Analog voltage of the ISETA signal (I suggest using an acurate bench multimeter)
  • Analog input voltage from the opamp (input of the AD converter)
  • Digital value of the (*Reg).Buck.SetOutput variable

 This could give an indication what is going on. 

Best regards, Jiri

Hello Jiri,