Explanation of switch power adapter voltage benchmark type 2020-826
14 14:50:44 1.
Switch power adapter voltage standards according to the working principle of the division,
Parallel benchmark parallel benchmark (
As shown in figure 2 -
56. Benchmark is parallel with the load in parallel, the reference voltage Uref = Uin -
Uin * Rs, when the input voltage or load current I hair production, the benchmark by adjusting the l to keep the stability of the U. Parallel benchmark only two pins, cheaper price, is suitable for the occasion of load current changed little;
Defect is a relatively large power consumption, the input voltage adjustment rate is not very ideal, common benchmark model in parallel are LM358, AD589, etc.
Series standards series benchmark,
As shown in figure 2 -
57. Benchmark series with the load is connected in series, Uref benchmark voltage = Uin -
* Rs. Because the lq, is small and keep constant when U.
Benchmark or changes, l series by adjusting the internal resistance to maintain the stability of U R. Series benchmark usually have three pins, input, output, pressure difference and l. Can do smaller, therefore more suitable for a battery-powered occasions, common benchmark series models are AD581, REF192, etc.
6 v power adapter voltage standards according to the technology division,
Zener datum zener datum (
The advantage of low cost, small packaging, wide working voltage range;
Defect is big power consumption, low initial accuracy, temperature coefficient, input voltage adjustment rate is not good, when used according to the power supply voltage and load current through a resistor with a certain current, in order to keep the output voltage stability, zener benchmark is not high, usually used for cap position or used as voltage.
Buried zener benchmark buried zener benchmark (
Has the very high initial accuracy, small temperature coefficient and good long-term drift stability, lower noise, the overall performance is better than other types of benchmark, reason often used in 12 or higher resolution system, yan Richard zener benchmark usually requires more than 5 v power supply voltage, and consume hundreds of microamps of current, the price is more expensive.
Band gap base band gap reference (
Initial accuracy, temperature coefficient, long-term drift, noise voltage from low to high performance indicators such as wide coverage, more suitable for 8 ~ 10 precision of the system. This class benchmarks are designed for the purposes of usually type static current as small as a few microamps, input, output, low voltage difference surface is suitable for the battery products, due to the application range is very wide. Taken together, the band gap benchmark performance is good, price moderate, is the most valuable references.
XFET references are XFET is a new type of voltage benchmark, its performance level between band gap and the zener datum, the static current is very small coke for 3 v voltage system, and still can maintain good performance and XFET references are three obvious characteristics: one is under the condition of the same working current, its peak peak noise voltage is usually lower than the band gap reference several times;
And XFET references are within the scope of industrial temperature curve is very flat or linear temperature coefficient, and the band gap and the temperature coefficient of zener benchmark curve is often non-linear temperature range at both ends and the nonlinear is not convenient to modify it by software;
A third is XFET references are has excellent long-term drift stability.