company blog about Recycle Microchip Special-Purpose ADC:Display ADC,Dual-Slope ADC,BCD And Binary ADC

Recycle Microchip Special-Purpose ADC:Display ADC,Dual-Slope ADC,BCD And Binary ADC

Shenzhen Mingjiada Electronics Co., Ltd. has specialised in the field of electronic component recycling for many years and is a professional provider of inventory management and recycling services within the industry. We purchase genuine, original manufacturer products, obsolete stock, discontinued products and idle chips at highly competitive prices, helping businesses to rapidly reduce inventory, recover capital and lower warehousing and management costs.

Key Advantages of Our Recycling Services

1. Professional Assessment, High-Value Buyback, Transparent Pricing

We have a professional technical team that conducts precise authentication of original, refurbished and disassembled equipment, ensuring the elimination of counterfeit and substandard products.

Our quotations closely follow international market trends and include a scarcity premium; our prices are 10%–15% higher than those of our competitors, with even more favourable rates available for bulk consignments.

No hidden fees: on-site collection, transport, testing and packaging are all included, ensuring complete transparency throughout the process

2. Efficient Response, Cash Settlement, Rapid Cash Flow

24-hour online quotations; on-site valuation within 48 hours (nationwide coverage)

Immediate cash settlement upon successful valuation (cash/bank transfer/wire transfer); large sums credited on the same day

We support purchases starting from a single item, bulk clearance and long-term procurement services, offering flexible solutions to meet corporate needs

3. Nationwide on-site service, one-stop end-to-end solutions

Service coverage includes Shenzhen, Hong Kong, Guangzhou, Shanghai, Suzhou, Beijing and major industrial cities across the country

Service process: On-site inventory → Testing and grading → Packing and removal → Payment settlement → Data destruction

Comprehensive solutions for factories’ slow-moving stock, surplus materials from engineering projects, leftover stock from export orders, dismantled circuit boards and goods seized by customs

4. Thirty years’ industry experience, an excellent industry reputation and long-term partnerships

Established in 1996, with 28 years’ experience in electronic component recycling and a global service network

We have served thousands of industrial, new energy and automotive electronics enterprises, with a repeat purchase rate exceeding 85 per cent

We also provide spot stock, empowering clients through dual channels of recycling and supply

Recycling Process

Submit inventory list: Clients provide model numbers, quantities, batch numbers, condition and packaging details

Precise Quotation: Mingjiada technical assessment → Quotation within 1 hour → Price confirmation

Collection/Logistics: Door-to-door collection (nationwide coverage) or client dispatch of samples; free of charge throughout

Inspection and Settlement: Incoming goods inspection → On-site cash settlement → Transaction completed

I. Display ADCs

Display ADCs are specialised ADCs designed for direct driving of LED displays and LCDs. Based on a dual-slope integration architecture, these chips integrate a seven-segment decoder, bit-selection drivers and polarity signal generation circuits. They can directly drive LCD or LED digital displays without the need for an additional MCU for digital decoding, making them a classic solution for digital voltmeters and handheld measuring instruments.

Representative model: TC7126 (3½-digit LCD direct-drive ADC). It integrates an on-chip clock, bandgap reference and auto-zero circuit; a complete measurement system can be built with only a few external RC components. With a resolution of 0.05%, it is suitable for low-cost panel metres.

Key Features

1. Built-in display driver logic, with time-division multiplexed output of segment codes and bit selection signals for direct connection to an LCD;

2. Built-in polarity and overflow indication outputs, with automatic out-of-range marking;

3. Based on the dual-slope integration principle, offering strong suppression of power-line noise;

4. Relatively low conversion rate, typically sampling several to tens of times per second, prioritising measurement accuracy over speed.

Typical applications: portable digital multimeters, industrial panel-mounted display units, and battery-powered measuring instruments.

II. Dual-Slope ADC

The dual-slope ADC is the underlying core architecture of Microchip’s specialised ADCs; most display ADCs are implemented based on the dual-slope principle. The conversion process is divided into an input integration phase and a reference reverse integration phase: the analogue input voltage is integrated for a fixed duration, after which the polarity is switched to reverse-integrate the reference voltage. The duration required for the integrator to return to zero is proportional to the input voltage; the digital value corresponding to the analogue signal is obtained by counting this duration, whilst an integrated automatic zero-reset cycle eliminates zero-drift error.

Representative models: TC514, TC14433 (3½-bit), TC7135 (4½-bit), TC500 series (up to 17 bits + sign bit, differential input, serial interface).

Key Features

1. Excellent common-mode rejection capability, capable of suppressing 50 Hz/60 Hz power-line interference, making it suitable for noisy industrial environments;

2. Conversion results are expressed as a ratio, making the device insensitive to short-term fluctuations in the reference source and clock, whilst ensuring high long-term accuracy;

3. Differential high-impedance inputs; automatic zero-reset technology reduces zero-point temperature drift;

4. A drawback is the slow conversion speed, making it unsuitable for high-speed signal acquisition;

5. The output format can be configured as BCD code or pure binary code, catering to both display and data acquisition requirements.

Typical applications: precision voltage measurement, weighing equipment, thermocouple temperature measurement, and low-frequency signal acquisition in laboratories.

III. BCD Output ADCs

BCD-type dual-slope ADCs output conversion results directly as decimal BCD code (8421 code), with each decimal digit encoded separately. This allows the data to be fed directly into a display decoder, supporting 3½-digit and 4½-digit decimal readouts, thereby eliminating the software overhead associated with binary-to-decimal conversion.

Representative models: TC7135 (4½-digit BCD output, ±20,000 counts), TC14433A (3½-digit BCD multi-channel output); the multiplexed BCD bus outputs the digits, sign and overflow signals.

Key Features

1. Outputs decimal BCD code, which is naturally suited to digital displays; no base conversion is required after reading by a microcontroller;

2. Supports over-range and under-range detection;

3. Multiplexed time-division output, minimising pin resource usage;

4. High accuracy and low non-linearity error; 4½-digit models achieve an accuracy of up to 50 ppm.

Typical Applications: Digital multimeters, process measurement displays, and devices requiring direct reading of decimal measurement values.

IV. Binary ADCs (Dedicated Binary Output ADCs)

Microchip’s dedicated binary ADCs are also based on a dual-slope integration architecture. They output pure binary code (including a sign bit), providing 15-bit or 17-bit binary data plus a sign bit, rather than BCD decimal code. These are designed for data acquisition and transmission to host computers, rather than for directly driving seven-segment displays.

Representative models: TC850 (15-bit binary ADC, up to 40 conversions per second, parallel binary output), TC500 series (17-bit + sign bit, serial binary interface).

Key Features

1. Conversion results are output directly as two’s complement binary, facilitating numerical calculations, storage and communication uploads by the MCU;

2. Retains the advantages of the dual-slope architecture: high immunity to interference, high precision and differential input;

3. Choice of parallel or serial digital interfaces;

4. Capable of detecting over-range and under-range input conditions.

Typical Applications: High-precision data loggers, industrial sensor data acquisition, embedded measurement systems, and scenarios requiring measurement values to be fed into a processor for algorithmic processing.