PSoC4 VDAC function

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chme_4646286
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PSoC4100S+系列提供了两个IDAC组件;

目前项目中需要VDAC,有没有什么办法可以把IDAC转换为VDAC呢?

如果可以,需要怎么实现,有无参考示例可以提供呢?

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MiNe_85951
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AN64275 will be helpful to you.

 

AN64275 URL

https://www.infineon.com/dgdl/Infineon-AN64275_PSoC_3_and_PSoC_5LP_Getting_More_Resolution_from_8-Bi...

 

PSoC4 has two 7bit IDAC.

If you set one IDAC to 609.6uA(4.8uA/bit) and the other IDAC to 76.2uA(0.6uA/bit), it will be 10bit.

 

9bit : 304.8uA (IDAC 6bit : setting 609.6uA)

8bit : 152.4uA (IDAC 5bit : setting 609.6uA)

7bit : 76.2uA (IDAC 4bit : setting 609.6uA)

...

4bit : 9.6uA (IDAC 1bit : setting 609.6uA)

3bit : 4.8uA (IDAC 0bit : setting 609.6uA)

2bit : 2.4uA (IDAC 2bit : setting 72.6uA)

1bit : 1.2uA (IDAC 1bit : setting 72.6uA)

0bit : 0.6uA (IDAC 0bit : setting 72.6uA)

 

Regards,

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MiNe_85951
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50 likes received 500 replies posted 50 solutions authored

Hi,

 

First of all, Converts the IDAC output in PSoC4 to voltage with an external resistor.

Since the impedance increases due to this external resistance, the operational amplifier inside the PSoC4 is used as a buffer.

Please refer to the connection below.

MaMi_1205306_0-1655698750799.png

Regards,

chme_4646286
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Hi MaMi_1205306;

Thanks for your reply;

Referring to the block diagram provided, an IDAC component and amplifier component are required in the schematic;

How to connect the two components? How should the amplifier components be configured?

Is there sample code or application note references?

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MiNe_85951
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Hi,

 

I configured a circuit with PSoC Creator 4.4.

The circuit diagram is as follows:

MaMi_1205306_0-1655706716744.png

There are two methods, one using "Idac" and the other using "PWM".

I think that IDAC can achieve higher accuracy than PWM.

 

The firmware only initializes each component and changes the IDAC current value and PWM Duty.

 

Regards,

chme_4646286
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Hi MaMi_1205306;

Thanks for the example provided;

The IDAC+Opamp component method is more applicable;

An additional question: The resolution of the IDAC component is 7bit, so the resolution of the converted VDAC should also be 7bit;

is there a way to improve the accuracy of the VDAC? For example, the resolution reaches 10bit

MiNe_85951
Level 7
Level 7
Distributor - TED (Japan)
50 likes received 500 replies posted 50 solutions authored

 

AN64275 will be helpful to you.

 

AN64275 URL

https://www.infineon.com/dgdl/Infineon-AN64275_PSoC_3_and_PSoC_5LP_Getting_More_Resolution_from_8-Bi...

 

PSoC4 has two 7bit IDAC.

If you set one IDAC to 609.6uA(4.8uA/bit) and the other IDAC to 76.2uA(0.6uA/bit), it will be 10bit.

 

9bit : 304.8uA (IDAC 6bit : setting 609.6uA)

8bit : 152.4uA (IDAC 5bit : setting 609.6uA)

7bit : 76.2uA (IDAC 4bit : setting 609.6uA)

...

4bit : 9.6uA (IDAC 1bit : setting 609.6uA)

3bit : 4.8uA (IDAC 0bit : setting 609.6uA)

2bit : 2.4uA (IDAC 2bit : setting 72.6uA)

1bit : 1.2uA (IDAC 1bit : setting 72.6uA)

0bit : 0.6uA (IDAC 0bit : setting 72.6uA)

 

Regards,

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chme_4646286
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Hi MaMi_1205306;

I got it,thans very much;

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MiNe_85951
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Note :

The ideal idac and opamp have 10-bit performance, however the effective number of bit (ENOB) is low due to the characteristics of the actual idac and the input current of the opamp.

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chme_4646286
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Hi MaMi_1205306;

What do the two macro definitions on page 6 of the AN64275 datasheet mean?

IDAC1_MSD_SOURCE and  IDAC2_LSD_SOURCE;

chme_4646286_0-1655804218434.png

PSoC Creator Gererated source does not have this definition;

chme_4646286_1-1655804403602.png

Can I consider IDAC1_MSD_SOURCE equivalent to IDAC7_1_POL_SOURCE?

 

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MiNe_85951
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Since the component names are set below, the generated source names are "IDAC1_MSD" and "IDAC2_LSD".

MaMi_1205306_1-1655805534889.png

API of PSoC3/PSoC5LP and PSoC4 are slightly different. 

 

However, the following may be a clerical error:

MaMi_1205306_2-1655805699180.png

Probably the following correctly : 

IDAC1_MSD_SetPolarity(IDAC1_MSD_SOURCE);

IDAC2_LSD_SetPolarity(IDAC2_LSD_SOURCE);

 

Since these initial settings are set in the GUI of the IDAC component on PSoC Creartor, I think it is not necessary to write "Sets both IDACs to source current" and "Sets proper range" in main.c again.

 

Regards,

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chme_4646286
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Sorry, I didn't pay attention to the top-level component naming;

I understand;thank you very much;

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