Adjustable resistor with low cost and high precision and control method

Abstract

The invention provides an adjustable resistor with low cost and high precision. The adjustable resistor comprises an MCU, a short circuit switch and an adjustable resistor module, wherein a group of resistance output interfaces are arranged at the output end of the adjustable resistor module, the short circuit switch is connected to the opening side of the adjustable resistor module in parallel, and a group of SOUT switches are serially connected between the short circuit switch and the resistance output resistances; and the short circuit switch, the adjustable resistor module and the SOUT switches are connected with the MCU respectively. The invention also provides a control method corresponding to the adjustable resistor. The adjustable resistor has the advantages that various devices inthe digital adjustable resistor can be realized by using common devices, the selective range of resistance value is wide, the selection cost of resistors is low, and moreover, resistance output withsuperhigh precision can be further realized.

Description

technical field [0001] The invention relates to the field of electronic technology, in particular to a low-cost and high-precision digital adjustable resistor and a control method. Background technique [0002] At present, in the process of testing the temperature and withstand voltage of the circuit, it is necessary to use an adjustable resistor as a test source. However, the existing adjustable resistors have the following defects: [0003] 1. The current adjustable resistors (such as TPL501-1000) generally have an accuracy error of 20%, their accuracy is too low, and their withstand voltage is also low (generally only tens of volts), which cannot meet the current test requirements at all; At the same time, the precision errors of different types of adjustable resistors are different, and the precision errors are not linear, which also makes it impossible to use algorithms for compensation; [0004] 2. The current digital adjustable resistor uses resistors connected in s...

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Problems solved by technology

[0003] 1. The current adjustable resistors (such as TPL501-1000) generally have an accuracy error of 20%, their accuracy is too low, and their withstand voltage is also low (generally only tens of volts), which cannot meet the current test requirements at all; At the same time, the precision errors of different types of adjustable resistors are different, and the precision errors are not linear, which also makes it impossible to use algorithms for compensation;

[0004] 2. The current digital adjustable resistor uses resistors connected in series, so when using it, it needs to use precision resistors with multiple resistance values ​​to realize it, which makes the selection of resistors difficult and the cost is relatively high;

[0005] 3. The current digital adjustable resistor cannot realize the resistance output of 0Ω resistor;

[0006] 4. The current digital adjustable resistor cannot realize the resistance output of infinite resistance;

[0007] 5. Most of the current adjustable resistance modules have only one communication interface, which cannot be compatible with various circuits, which will lead to increased development costs;

[0008] 6. In the current algorithm of NC adjustable resistors, because the resistors in multiples are directly connected in series and parallel, each resistor has a certain error, which leads to a decrease in loading accuracy; at the same time, the existing NC can The algorithm for adjusting the resistance does not consider the on-resistance of the switch, resulting in a further reduction in loading accuracy, and the loading error value cannot be known

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