By LEIDITECH | 26 February 2024 | 0 Comments
What is car load sheddingLoad dump
1.What is throwing load
Throw load，In EnglishLoad dump，It refers to the moment when the power supply and load are disconnected，Sudden changes in power supply voltage due to sudden load changes。In the field of automotive electronics，Load shedding refers to the process of charging a battery，DisconnectalternatorThe connection with the battery causes a large voltage spike in the generator output，Thereby posing a threat of damage to other equipment connected to the generator power supply。
Car load sheddingThere is a distinction between single throw and double throw，Only cutting off the generator as a single load throw；Only cutting off the battery is a single throw of the battery；Simultaneously cutting off the generator and battery is called a double throw。Due to the high reliability of the automotive operation process，ISOOrganizational load test developed by the organization，It must have its inherent rationality。The load test is a very rigorous destructive test。
2. When to unload 7637-5A/5B
Car load shedding，Mainly affected by the maximum voltage、The influence of three factors: internal resistance and duration，How to control the comprehensive impact of these three factors is the key to our car's load shedding protection。
Regulation 12VElectrical systems and 24VTest levels and measurement methods for electrical conduction disturbances and their immunity along power lines of road vehicles with electrical systems。Among them, pulse waveform 5AAnd 5BTwo standard tests are the most destructive testing tests，It is also the most difficult test standard to pass。
7637-5AThe standard is an uninhibited waveform，7637-5BIt is a waveform with voltage suppression at the front end of the generator，Please refer to the waveform diagram below for details，When the internal resistance is the same，The size of the waveform area also reflects the magnitude of energy。
Shanghai Leiditech has its own laboratory，Can assist customers in conducting load drop testing，The following picture shows Shanghai Leimao helping clients with 5B test
3. 7637-5A/5BEnergy suppression design scheme for
At 5AIn the case of，The test pulse provides the worst-case scenario。At 12VIn the case of，Regulate itsUsThe range is from 79 volts to 101 volts，And the range of internal resistance is 0.5 to 4 ohms，The action time of surge voltage is 40msTo 400ms。If load protection is applied，Passed 10 relevant tests under the specified pulse，So it proves that this protection is qualified。
Shanghai Leimao is an electromagnetic compatibility solution design and device manufacturer，We have validated multiple solutions for this test，Provide various solutions for everyone one by one，Engineers can choose for themselves。
4. Structurally simpleTVSProtection plan
Shanghai Leimao launches a structurally simple load protection scheme，Just oneTVS
1）For 7637-5A Protection plan
For 24V System testingTVS data
|
雷卯TVS型号 |
供电电压 |
电压V |
内阻 Ω |
波长 ms |
测试次数 |
结果 |
|
SM8S33CA |
27 |
174 |
8 |
350ms |
10 |
PASS |
|
SM8S33CA |
27 |
174 |
4 |
350ms |
10 |
PASS |
|
SM8S33CA |
27 |
174 |
3 |
350ms |
10 |
PASS |
There are also the following test data for the 12V system
|
|
供电电压 |
电压V |
内阻 Ω |
波长 ms |
测试次数 |
结果 |
|
SM8S24CA |
13.5 |
87 |
2 |
200ms |
10 |
PASS |
|
SM8S24CA |
13.5 |
87 |
2 |
400ms |
10 |
PASS |
|
SM8S24CA |
13.5 |
87 |
1 |
400ms |
10 |
PASS |
|
SM8S24CA |
13.5 |
87 |
0.5 |
400ms |
10 |
PASS |
2）For 7637-5B Protection plan
Many cars come with limiters，It can ensure that the output surge does not exceed 5BSet value，Further reducing the risk of load shedding，For such requirements，We can choose a cheaper solution，For example, Shanghai Leimao'sSM5S24CASeries car useTVSAnd 6.6SMDJ24CA。
5. DC-DCWhat design considerations are there？
Due toTVSInherent characteristics，There will be a range between the clamping voltage and the working voltage，So 12VsystemDCDCVoltage withstand selection 40V, 24VsystemDCDCVoltage withstand selection 60V,If there is a need for low clamping voltageTVS，Shanghai Leimao has a dedicated low clampTVSmaterial。
The above explanation or specific explanation about throwing loadcircuit designdemand，Can apply Shanghai Leimao to electromagnetic compatibility professionalsEMCLittle brother consultation。
ShanghaiLei Mao ElectronicsProfessional provision of electromagnetic compatibility for customersEMCDesign Services for，Provide laboratory testing for free testing
Vehicle specification levelMini LEDDriver chip，Lei Mao has anti-static protection devices for you to
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