Bridge Electronics

The Mixed-Signal Design Problem

Mixed-signal interfaces bridge the gap between the analog physical world we live in and the digital universe of computers. Bridging the gap is not easy. Interfering noise sources, low level signals, and the inherent analog nature of sensors often make it difficult, and sometimes even impossible, to convert real world physical phenomena into useful digital signals at a reasonable cost and size. Some sensing materials, such as quartz, have desirable performance characteristics, like its insensitivity to changes in temperature, but the signal they generate in response to the physical phenomenon is often too small to be measured easily. One solution is to increase the size of the active element, but this solution is limited to applications where small size and low-cost is not important. Other sensors cannot be made practical by increasing their size. Alternative materials, which generate a larger signal, either do not have the desirable performance characteristics or they are too costly. Another aspect of the problem is that an engineer must usually custom design the interface circuitry for each application. The design process takes time and money, and the resultant circuitry increases cost, space and power consumption in the end product.

The Direct Digital Signal Conditioning™ Solution

Bridge Semiconductor’s Direct Digital Signal Conditioning technology provides a unique, elegant solution to the mixed-signal interface problem by rejecting many of the sources of noise and by inherently generating a digital output signal usable by a computer. DDSC technology measures signals one thousand times smaller than existing circuits, and is particularly applicable to charge generating sensors. DDSC enables sensing materials with desirable performance characteristics, but whose signals were heretofore too small to be measurable and used. Its inherent digital output and noise immunity eliminates the need to custom design an interface for each application. It also reduces power consumption and facilitates miniaturization. DDSC makes it possible for Transanalog Interface solutions to be created for high performance, low-cost sensing applications.

Direct Digital Signal Conditioning™ Benefits

Measures 1,000 times smaller signals
Very high dynamic range - 120 dB
Provides inherently digital output
Extremely small with very low power consumption
Defeats many noise sources

Applicable Sensors

DDSC technology works best with charge-generating or low-current generating sensors. The following is a list of applicable sensor-types:

Piezoelectric
Pyroelectric
Ion chambers
Photodiode
Capacitive
II-VI Semiconductors such as CdZnTe

How Direct Digital Signal Conditioning™ Works

A simple analogy to explain how DDSC technology works is to consider a bathtub being filled with water. The water level in the bathtub is the signal that DDSC needs to measure. DDSC works by trying to keep the level of water in the bathtub constant. If the level of the water goes up because more water is coming into the bathtub than going out the drain, DDSC removes the excess water in very precise, fixed amounts. If the water level goes down, it adds excess water in the same precise, fixed amounts. DDSC can add or remove the precise, fixed amounts as fast as needed to keep the water level constant. Every time one of the precise, fixed amounts is added or removed, the event is counted. The counting process is the inherently digital output. Error reduction is achieved by minimizing all of the ways water can leak from the bathtub.

DDSC can measure signals one thousand times smaller than other technologies while inherently providing a digital output. Transanalog Interfaces™ are created by combining DDSC technology with sensing materials that have outstanding performance attributes but whose output signals were previously too small to be measurable. Transanalog Interfaces™ are manufactured using proven high yield, low-cost volume manufacturing processes.