New Trend of Digital Multimeters chip · 2017-01-25 · New Trend of Digital Multimeters chip In...

New Trend of Digital Multimeters chip

© 2016 HYCON Technology Corp. www.hycontek.com

http://www.hycontek.com/


Table of Contents

1. Foreward ........................................................................................................................... 錯誤! 尚未定義書籤。

2. Technological progress of protable electrical measurement meter .................. 錯誤! 尚未定義書籤。

3. Function introduction of new chip trend .................................................................. 錯誤! 尚未定義書籤。

3.1. Programmable switch network .............................................................................. 錯誤! 尚未定義書籤。

3.2. High-resolution Σ-Δ ADC ....................................................................................... 錯誤! 尚未定義書籤。

3.3. Digital RMS circuit ................................................................................................... 錯誤! 尚未定義書籤。

3.4. Operational amplifier ................................................................................................ 錯誤! 尚未定義書籤。

3.5. Low-pass filter ............................................................................................................ 錯誤! 尚未定義書籤。

3.6. Peak hold measurement circuit .............................................................................. 錯誤! 尚未定義書籤。

3.7. Inrush current measurement....................................................................................................................... 10

3.8. Temperature sensor ....................................................................................................................................... 10

3.9. Standard serial interface ........................................................................................... 錯誤! 尚未定義書籤。

3.10. MCU .............................................................................................................................. 錯誤! 尚未定義書籤。

3.11. Wider temperature usage range.............................................................................. 錯誤! 尚未定義書籤。

4. References ......................................................................................................................... 錯誤! 尚未定義書籤。

5. Modificaiton record ....................................................................................................... 錯誤! 尚未定義書籤。

© 2016 HYCON Technology Corp www.hycontek.com

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1. Foreword

When repairing machine or conducting experiments, electrical/electronic technicians often use analogue

multimeters or digital multimeters (DMM). Previously, the portable digital meter industry usually adopts the analog to

digital converter (ADC), provided by large international companies, designed for digital multimeters to convert the

inputted analog signals to digital signals and then further process the signals. However, the product has long life cycle,

the product also has low demand and various different types; therefore, these large international companies have no

longer designed new ADC for digital multimeters, or even leaved the market of the ADCs designed for digital

multimeters. A digital multimeter only needs a chip and resistors, capacitors and protection components to finish a

product, so the threshold is low and the market of the industry is also limited; therefore, price war must finally take

place; further, the profit of the product is also lower than consumable products. For digital multimeters, the core is the

analog to digital converter; the large international companies, such as American Fluke, can design the dedicated DCC

chips by themselves; on the contrary, as the domestic portable meter industry is smaller the other countries, the

domestic companies cannot design the dedicated DCC chips by themselves.

The document will introduce the DMM dedicated chips, including the HYCON HY12P-series

Mixed-Signal Microcontroller, and HYCON HY313x-series Analog Front End.。

2. Technological progress of portable electrical measurement meter The first kind of portable electrical measurement meter is the analogue multimeters; this electrical

measurement meter is of low price, but has low accuracy, low resolution, no input protection and is poor in

function.

After the development of IC started, chip providers designed the analog to digital converter, the

handheld manual range digital multimeter was developed, which not only had the voltage, resistance and

current measurement functions, but also provided the capacitance, frequency and temperature measurement

functions; further, DMM manufacturers further added the input protection circuit to this meter; however,

almost all functions should be switched by an additional circuit, so users should manually select the range,

which is inconvenient in use.


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In order to simplify the operation, chip provides designed the analog to digital converter dedicated for

the DMM; for the reason, the handheld auto range digital multimeter was developed, which usually designed

all functions into the chip, so it only needed to add the resistors and capacitors; further, users did not need to

manually select the range.

However, users had new requirements, which were high accuracy, high resolution and special functions,

such as computer connection function; thus, chip providers designed a component for the analog front end

dedicated for the DMM, or combined the analog front end with the MCU; the chip integrated with the MCU

satisfied the new requirements. However, previously, the chip of this kind of product could only provide the

voltage, resistance and current measurement functions, but needed additional circuits to realize other

functions; thus, the product was not an ideal product.

For the purpose of satisfying the above new requirements, HYCON provides new-generation DMM

dedicated chips, such as HY12P-series and HY313x-series chips to solve the problems.

3. Function introduction of new chip trend

The new trend of the portable digital meter industry should have unique product function planning in

order to prevent from price war, such as intelligent electrical meter; moreover, more flexible DMM

dedicated chip is necessary; the functions of the new chip trend can be classified into the following items:

3.1. Programmable switch network

Previously, the DMM dedicated chips had constant function and range switch networks; the advantages

of which were easy to design; however, unique product function planning cannot be realized by flexibly

switching multi-function network. All of the DMM dedicated chips introduced by the document have a

programmable switch network, such that the portable digital meter can have more space for development.

Please refer to HY313x configuration settings and HY12P65 configuration settings for more information

about detail function network settings.


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RLU

capacitor array

RLD

RLU

RLD

FBSENSE

PA<0>

PA<1>

PA<2>

PA<3>

PA<4>

PA<5>

PA<6>

PA<7>

VREF

AGND

10M

1M

100k

10k

1k

PTC + 100

VOLT/OHM/CAP/DT

OH

M/C

AP

/DT/

mV

PS7

DS7

FS7

SS7

PS6

DS6

FS6

SS6

PS5

DS5

FS5

SS5

PS4

DS4

FS4

SS4

PS3

DS3

FS3

SS3

PS2

DS2

FS2

SS2

PS1

DS1

FS1

SS1

PS0

DS0

FS0

SS0

ACC<6:0>

SMODE<5>

SM

OD

E<4

>

SVSO1

SV

SO

2

SV

SO

2

SV

SO

2

SCP

SCN

PA<8>PS8

DS8

FS8

SS8

PA<9>PS9

DS9

FS9

SS9

AGND VSS VDD

SV

DD

SV

SS

SA

GN

D

MUX

VREF VDS<17>VDS<16>VDS<15>

VDS<1>VDS<2>VDS<3>

AGNDN<9>AGNDN<8>AGNDN<7>AGNDN<6>

PB<7>

AGNDP<9>AGNDP<8>AGNDP<7>AGNDP<6>AGNDP<0>

FUVR<3:0>SMODE<3>

CPO

VREF

PB<0>PB<0>900K

PB<8>PB<8>100KSDIO

AGND

30

7.5p

1 0 0 0 0 0 0

SA

GN

DS

VD

DS

VS

SS

VS

O1

SV

SO

2S

CP

SC

NSMODE<3:0> C

PO

0 1 0 0 0 0 0

0 0 0 0 X0 0 0 1 X

0 0 1 0 0 0 00 0 1 0 X0 0 1 1 X0 1 0 0 X0 1 0 1 X0 1 1 0 X0 1 1 1 X

0 0 0 0 0 0 0

0 0 0 1 0 0 01 0 0 1 0 0 00 1 0 0 1 1 00 0 1 0 1 0 1

1 0 0 0 0 0 00 1 0 0 0 0 0

1 0 0 X 01 0 0 X 1

0 0 1 0 0 0 01 0 1 X 01 0 1 X 11 1 0 X 01 1 0 X 11 1 1 X 01 1 1 X 1

0 0 0 0 0 0 0

0 0 0 1 0 0 01 0 0 1 0 0 00 1 0 0 1 1 00 0 1 0 1 0 1

▲HY3131 Analog Switch Network

3.2. High-resolution Σ-Δ ADC

Previously, the ADCs of the DMM dedicated chips manufactured by large international companies

adopted the double slope integrating structure. however, the conversion speed of the analog to digital

converter of the structure was slow, and the quality of the integrating capacitor could influence the overall

stability and error of the converter. In general, the integrating capacitor needed to use high-cost materials,

such as MPE or MPP, and was hard to achieve high resolution.


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In recent years, the Σ-ΔADC is gradually used for industrial controls and high-class meters; the most

important advantage of the ADC is that the ADC has less peripheral circuits and high conversion speed, high

resolution and high accuracy; besides, the ADC is not easily influenced by the 50/60 HZ frequency of the

power system; moreover, the peripheral cost of the ADC is lower than that of the double slope integrating

ADC. 。

3.3. Digital RMS circuit

The AC signal measurement is necessary for either voltage or current. However, , the AC signal

measurement circuit could be divided into the average response circuit measurement circuit and the true

RMS conversion dedicated component measurement circuit previously; both of which needed additional

components. All of the DMM dedicated chips introduced by the document have a high-precision Σ-ΔADC,

and the conversion result will be processed by the high-speed calculation of the inner hardware to realize the

digital RMS and inrush current measurement functions; besides, which can be integrated with the peak hold

measurement to realize higher peak factor signal measurement.


page6



SADFRN<1:0>

OP1OOP2O

PB<4>PB<7>

MUX

SADFIP<1:0>

ADFIP

RLUAGNDPB<3>PB<5>

MUX

SADFIN<1:0>

ADFIN

AD2IN

FBREFOVREF

PB<6>

MUX

SADFRP<1:0>

ADFRP

ADFVR+

RLUAGNDPB<3>PB<5>

MUX

ADFRN

ADFVR-

AD2IP

ADFIG[1:0]ADFRG

ΣΔAD

VR+ VR-

ADF_CLKENAD2

+ VR:x1,x1/3 -

1bit

Comb Filter

3

ADFOSR[2:0]

19bit

ADCIFInterrupt

AD2

INX

ADFCHP

OP1OOP2O

PB<4>PB<7>

MUX

SADPIP<1:0>

ADPIP

RLUAGNDPB<3>PB<5>

MUX

SADPIN<1:0>

ADPIN

ADPIN

ADPIP

ADPIG[1:0]ADPRG

ΣΔAD

VR+ VR-

ADF_CLKENAD3

SI:x1/2,x1,x3/2,x2

+ VR:x1,x1/3 -

1bit

Comb Filter

3

ADFOSR[2:0]

19bit

ADCIFInterrupt

AD3

INX

ADPCHP

MUX

FAST ADC MUL

LPF/n _

X

LPFBW<2:0>

19

FAST ADC

LPF/n

_Y

LPFBW<2:0>

19

38MUX

SD

O23

SI:x1/2,x1,x3/2,x2

HPF/n

HPF/n

Y

MUXAD3DATA<18:0>AD2DATA<18:0>

SD

O23

AD2<18:0> Peak Hold

EN

PK

H

PKHMAX<18:0>

LPFDATA<18:0>AD2<18:0> PKHMIN<18:0>

AD1<23:5>

PK

HS

EL<

1:0>

MUXAD3_LPF<18:0>AD2_LPF<18:0>

SD

O23

LPFDATA <18:0>

RMSDATA [37:0]

AD2DATA<18:0>

AD3DATA<18:0>

AD3_LPF<18:0>

AD2_LPF<18:0>

SV

XI

Square

LPF/n

LPF/n

RMS_V

RMS_I

38

38

X

▲ RMS measurement structure block diagram of HY3131

3.4. Operational amplifier

In general, under the lower voltage range, current range and temperature measurement function, small

signals are amplified to the allowable range of the converter and then the signal quantization conversion is

executed. The DMM dedicated chips introduced by the document can be integrated with the

programmable switch network to form a signal buffer or non-inverting amplifying circuit.。


page7



OP1 OP1O

SENSEFB

RLUAGND

PB<1>PB<2>PB<3>

PB<0>MUX

IN_OP2

OP2

SENSEFB

RLUAGND

PB<1>PB<2>PB<8>

PB<0>MUX

IN_OP1

OPS<2>

OPS<2>

OPS<1>

OPS<1>

OP2O

OPCHP<1:0>

OP

1N

OP

1O

OP

2N

OP

2O

◄ HY3131 OPAMP Switch Network

3.5. Low-pass filter

。In some electromechanical measurement applications, the signals to be measured may include surges

or other high-frequency signals. The low pass filter can be used to filter out the high-frequency signals, and HY313x can use the OP inside the chip to realize the function of the third-order LPF.

▲According to the above figure, the original waveform is 1V/60Hz plus 0.1V/4KHz; after


page8



the waveform passes through the low pass filter, the waveform is filtered to be 1V/60Hz.

VSENSEFB

RLUAGND

PB<1>PB<2>PB<3>

PB<0>MUX

SOP2P<2:0>

IN_OP2

OP2

OPS<2>

OPS<2>

OP2O

OP

2O

OP

2N

1.21k 470nF

OP1 OP1O

VSENSEFB

RLUAGND

PB<1>PB<2>PB<8>

PB<0>MUX

IN_OP1

SOP1P<2:0>

90kAGND

10k

OPS<1>

OPS<1>

OPCHP<1:0>

OP

1O

OP

1N

4.02k 2.47k

100nF100nF

AGND AGND

PB

<2>

▲The function of the third-order LPF is realized by HY3131.

3.6. Peak hold measurement circuit

Some electromechanical measurement applications need to measure the peak value; then, it is necessary

to use the peak hold circuit to lock the voltage, and the use the analog to digital converter to convert the

voltage. However, the capacitor used by this kind of circuit to lock the voltage tends to be influenced by the

external environment. All of the DMM dedicated chips introduced by the document have the digital peak

hold function to compare the analog-to-digital conversion results so as to achieve higher accuracy.

Peak Hold

ENPK

H

PKHMAX<18:0>

LPFDATA<18:0>AD2<18:0> PKHMIN<18:0>

AD1<23:5>

PKH

SEL<

1:0>

◄ HY3131 Peak Hold Block Diagram

INPUT3

26

+

-

OUTPUT

3

26

+

-

▲ Low Drift Peak Detector


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3.7. Inrush current measurement

In recent years, some tong-test ammeter providers proposed the in-rush current measurement, which

means “in a three-phase motor, the in-rush current usually lasts 75~150mS and has a current peak between

500%~1200%, which is short but the instantaneous increase will result in some problem”. All of the DMM

dedicated chips introduced by the document have the swift AC signal conversion function, which can

capture the in-rush current.

Cur

rent

In-Rush Current100 ms

Time

Running Current

▲ In-Rush Current

3.8. Temperature sensor


page10


http://terms.naer.edu.tw/detail/91791/?index=1


Some portable electrical measurement devices have the temperature measurement function in addition

to the electricity measurement and component measurement functions. The most frequently-used

temperature detectors are the following 4 types: the thermocouple detector, the resistance temperature

detector (RTD), the thermistor detector and IC detector. In general, the portable electrical measurement

devices adopt the thermocouple measurement structure; its principle is that the contact of two metals will

result in the voltage caused by Seebeck effect. However, as the voltage is 0 when the temperature to be

measured is equal to the environmental temperature, it is necessary to perform “Cold-Junction

Compensation”. All of the DMM dedicated chips introduced by the document have a temperature sensor.

▲ Temperature Measurement Circuit. (data resource: Texas Instruments OPAx235

Datasheet)

3.9. Standard serial interface

HY12P-sereis chips have the UART (Universal Asynchronous Receiver/Transmitter) interface. The

new-generation portable digital meters usually have the UART interface and the computer communication

function, which can achieve the automatic test and the automatic calibration functions to reduce to cost of

the manpower. The UART interface can completely change the usage habit of users; for example, the

product can be integrated with the wireless communication module, such as Bluetooth or WiFi module to

communicate with a smart phone or tablet computer to separately perform measurement, displaying and data

statistics analysis.


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HY313x-sereis chips have the SPI interface; the component is a DMM analog front end dedicated chip,

which can be integrated with the MCU control chip to realize the products with special displaying screens, such as the following products. The SPI is the standard serial transmission interface most frequently used in microcomputer systems, and can provide higher transmission speed. 3.10. MCU

HY12P-series chips not only have the DMM dedicated analog front end circuit, but also is integrated with the MCU having the 80bit RISC, which is suitable for middle-class or low-class meters, and can save the circuit layout space for the products in order to reduce the size of the products. 3.11. Wider temperature usage range

Previously, the operation temperature of the DMM dedicated chips manufactured by the large international companies is about 0 ℃~50℃; however, some users need wider usage range; thus, the operation temperature of all products of HYCON is -40 ℃~85℃. 4. References

HY3131 (50,000 counts DMM Analog Front End) Datasheet HY12P65 (DMM Specialized IC Embedded Digital T-RMS) Datasheet HY12P (Digital Multimeter) Family User’s Guide HY313x configuration settings HY12P65 configuration settings

5. Modification record

The following content describes the major differences from the document, and the changes of punctuation

marks and character forms are not described in the following content. 。

Date Document

version Page Remark

2016/08*20 V01 ALL New release


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