Peripheral - Delta Sigma Demodulator (DSD)

DSD
Delta Sigma Demodulator
DSD
Delta Sigma Demodulator
Highlights
XMC4000 provides four delta sigma
demodulator channels and one carrier
generator.
It is tailored to demodulate a bitstream
from an external delta sigma modulator.
This can be used for isolated current/voltage
measurement and for sensor interfaces.
Key Feature
Customer Benefits
Adjustable CIC filter
External sigma delta modulator can be
connected directly to XMC without ASIC
Parallel auxiliary CIC filter with boundaries
Simultaneous overcurrent/voltage detection
with programmable boundary interrupt
Resolver support
Resolver excitation and feedback reading with
full hardware support saving external ASIC
2013-10-08
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DSD
Adjustable CIC Filter (1/2)
 Each DSD Channel supports 4 types of CIC Filters:

CIC, CIC², CIC³, CIC F.
 The decimation factor can be selected independent from other channels:

4 to 256
2013-10-08
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DSD
Adjustable CIC Filter (2/2)
Filter comparison
Responsetime
[μs]
Decimation factor
comparison
*1
Maximum output
[Bit]
D: 32
6
9.6
11.1
6.6
6.4
12.8
12.8
6.4
3.2
CIC
D: 128
25.6
16
11
D: 64
*2
11
13
15
6.4
3.2
CIC²
CIC³
CIC F
Responsetime Update Time
[μs]
[μs]
Maximum
output
[Bit]
*1: Sample frequency 10Mhz, Decimation factor: 32
*2: Sample frequency 10MHz, Filter type: CIC³
2013-10-08
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DSD
Parallel Auxiliary Filter With Boundaries
 Each DSD Channel has a Auxiliary CIC Filter

4 Filter types can be selected (CIC, CIC², CIC³, CIC F)

Decimation factor between 4 to 32

Hardware Boundary check with interrupt to reduce CPU Load
2013-10-08
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DSD
Resolver Support (1/6)
 Hardware for Resolver Support

Carrier Generator

Rectify

Integration
(part of DSD Channel)
(part of DSD Channel)
arctan  =
2013-10-08
sin 
cos 
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DSD
Resolver Support (2/6) – Carrier Generator
 Carrier Generator

Hardware generated waveform without CPU load

Waveform: Sine, triangle and rectangle

Output frequency between 3,7kHz and 58,6kHz

Signed signal for rectification
*)
* Peripheral Clock 120MHz
2013-10-08
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DSD
Resolver Support (3/6) - Rectifier
 Rectifier

Hardware rectifier for carrier cancellation

Hardware sign delay capture

Adjustable sign delay compensation
2013-10-08
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DSD
Resolver Support (4/6) – Rectifier
 Sign delay compensation
2013-10-08
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DSD
Resolver Support (5/6) - Integrator
 Integrator

Hardware Integrator

Adjustable Integration window

Continuous and Trigger Mode
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DSD
Resolver Support (6/6) - Overview
 1
 2
 3
2013-10-08
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DSD
System Integration
XMC4100
XMC4200
XMC4400
XMC4500
●
●
DSD is connected to GPIO, ERU, NVIC
and DMA.
In many applications it is mandatory to
synchronize the carrier generator, the
DSD and the external DSM. Therefore
the DSD has implemented the carrier
generator and provides a clock via GPIO
for the DSM.
 Target applications
The connection to the ERU enables a
various of trigger sources.

Motor Control

Isolated Current measurement

Isolated Voltage measurement
2013-10-08
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Application Example
Isolated Current Measurement
Overview
All three currents are
measured in phase
with a DSM. The bits
stream allows a costefficient digital
isolation. The
microcontroller is
isolated against the
high voltage part.
Also a benefit is the
good signal to noise
ratio based on the
oversampling.
In Brief
In many high voltage applications a isolation is needed.
The DSD offers the possibility for a isolation of the XMC
MCU against the high voltage.
2013-10-08
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Application Example
Rotary Angle Detection via Resolver
Overview
The angle coming as sine
and cosine analog value
from resolver are multiplied
by the carrier signal. The
XMC DSD provides
hardware for carrier
cancelation and data
calibration.
In Brief
For a Resolver analysis a data processing is
necessary. The XMC offers many of these
calculation in hardware.
2013-10-08
In addition on high voltage
boards the resolver has to
be isolated against the high
voltage. In this case the
XMC is on the high voltage
side and the resolver is
isolated.
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General Information
 For latest updates, please refer to:
http://www.infineon.com/xmc4000
 For support:
http://www.infineonforums.com/forums/8-XMC-Forum
2013-10-08
Copyright © Infineon Technologies AG 2013. All rights reserved.
Page 15