PGA411-Q1: exciter signal generator

Dongbao Zhou

Part Number: PGA411-Q1

Hello,

I have some questions about the exciter signal generator of PGA411-Q1:

1. What's the typical value of Vdac in figure 13?

2. From figure 13, EXTOUT+1/2 EXTOUT_GT*Vdac=2.5, that's to say, if one of them is set, another is fixed. Why we set both of them?

3. What's the typical drive current for a resolver sensor? Typically, the parameter is not specified in the resolved datasheet. Does this parameter help us select EXTOUT_GL? Or in other words, how to select EXTOUT_GL?

Thanks.

Dongbao

over 6 years ago

0 Bala Ravi over 6 years ago

TI__Expert 6625 points

Hi Dongbao,
We've got your request. Our applications engineer will get back to as soon as possible.

Best Regards,
Bala Ravi

0 Clancy Soehren over 6 years ago

TI__Mastermind 23810 points

Dongbao,

1. VDAC is typically 2Vpp (this is shown on Figure 73 in the datasheet).

2. EXTOUT_GL allows for a fine gain setting, and EXTMODE is a more coarse gain setting. EXTOUT actually shifts the common mode voltage of the signal. That figure is a little misleading.

3. You could calculate the current by looking at the impedance of the resolver sensor and the recommended driving voltage range. EXTOUT_GL only helps set the amplitude. The PGA411 spec lists the typical amplitudes for every combination of EXTMODE and EXTOUT_GL.