#bestbooster

First, the input voltage V.I.N.: the transient limits of the 12 V batteries determine those of the input voltage IC Typically the car battery voltage is between 9V and 16V. The nominal voltage of the battery is 12V when the motor is switched off; the battery voltage is approximately 14.4V when the engine is running. However, under different conditions, the transient voltage may also reach ± ​​100V. The ISO 7637-1 industry standard defines the range of voltage fluctuations for automotive batteries. Any standard, as long as it is involved in vehicle safety, requires that the system have protection against overvoltage and under voltage. Second, heat: the cooling must be adapted to the DC-DC converter according to the minimum efficiency. If the airflow is poor or even air-free, be> 30 ° C, if there is a heat source (> 1W), the device heats up rapidly (> 85 ° C). For example, most audio amplifiers must be mounted on a heat sink and must provide good airflow conditions to dissipate heat. In addition, PCB materials and a certain copper zone contribute to improving the efficiency of heat transfer, in order to obtain the best dissipation conditions. If the heat sink is not used, the cooling capacity is limited to 2W at 3W (85 ° C). As the ambient temperature increases, the cooling capacity will be considerably reduced. When the battery voltage is converted to a low voltage output (e.g. 3.3V), the linear controller will consume 75% of the input power and the efficiency becomes extremely low. In order to provide 1W of output power, there will be 3W of power consumed as heat. By the ambient temperature and the thermal resistance of the shell / junction, the output power will be considerably reduced. For most high-voltage DC-DC converters, when the output current is between 150mA and 200mA, the LDO can provide higher performance. Convert the battery voltage to low voltage (e.g. 3.3V). When the power reaches 3W, you must select a high-end switch type converter that can provide more than 30W of output power. This is why major manufacturers, such as ANKAI, usually use switching power supply, and exclude traditional architecture based on the LDO. Third, the static (IQ) and power off (ISD) As the number of ECUs increases rapidly, the total current consumed by automotive batteries continues to grow. Some ECUs remain operational even when the engine is off and the battery is depleted. To ensure the IQ static operating current in the controllable range, most manufacturers have started to limit the IQ of each ECU. For example, the EU requirement is 100μA / ECU. The vast majority of EU automotive standards require a typical value for the IQ ECU of less than 100μA. Fourth, cost control: cost control and specification trade-offs is an important factor affecting equipment For mass production, the cost of design is an important factor to consider. The type of PCB, heat dissipation capacity, permissible encapsulation and other design constraints are actually limited by the budget of a particular project. For example, between the use of 4 layers FR4 and a single layer of CM3, the cooling capacity of PCB will be very different. The project budget will also create another constraint: the user can accept a higher cost of the ECU, but will not spend time or money for the transformation of the traditional design of power supply. For a portion of the new high-cost development platform, designers optimize the traditional design only with a simple cut. Fifth, positioning: the configuration of PCB and components in the design limits the overall performance of the power supply Structural design, positioning, noise sensitivity, multi-layered interconnections and other limitations of the board may impede the design of the circuit. Designers must balance overall system performance, mechanical constraints, and costs to the specific requirements of their product. Sixth, electromagnetic radiation The electric field will produce electromagnetic radiation, and the intensity of the radiation depends on the frequency and amplitude of the field. Electromagnetic interference generated by a working circuit will directly affect the other circuit. For example, interference from the radio channel may cause the airbag to malfunction. In order to avoid these negative effects, the manufacturer Ankai Tech Limited has developed the maximum radiation limits for the ECU In order to maintain electromagnetic radiation (EMI) in the controlled range, the type of DC-DC converter, peripheral components, panel layout and shielding are all selected with caution. After years of experience, IC designers from Ankai Tech Limited have developed a variety of EMI control technology. External clock synchronization, operating frequency superior to AM modulation frequency band, integrated MOSFET, flexible switching technology, spread spectrum technology have been developed over the past few years.