Looking for a DC/DC step-down chip

liushiming82

Looking for a DC/DC step-down chip [Copy link]

 

Hello everyone, I now want to need a DC/DC step-down chip. The input requirement is DC20V 3.25A and the output is DC 3.4V 14A. If there is a constant source, it would be the best. Thank you. If you have any, please contact me at QQ 340150293

qiushenghua

With such a large current, consider external MOSFET [attach]407628 [/attach] [attach]407629 [/attach]

qwqwqw2088

It is better to have a range of input voltage, which makes it easier to choose chips

liushiming82

qiushenghua posted on 2019-3-29 13:59 For such a large current, consider external MOSFET

I am currently using sc8002, but the current can only reach 10A

whuer

liushiming82 posted on 2019-3-29 18:16 I am using sc8002 now, but the current can only reach 10A

The MOS I chose has a problem

qiushenghua

liushiming82 posted on 2019-3-29 18:16 I am using sc8002 now, but the current can only reach 10A

Can you post the schematic diagram of this part? Let's see what the problem is.

liushiming82

qiushenghua posted on 2019-4-1 14:07 Can you post the schematic diagram of this part? Let's see what the problem is.

Of course you can

qiushenghua

I'm afraid that SC8002 is not suitable for your application. ISENSE limits the peak current of the inductor, and the current limit value is 30mV. However, the resistance of the sampling resistor R_ISENSE cannot be too small. It is generally not recommended to use a resistance value below 2mR (after parallel connection). Too small a resistance value may cause unstable operation. The operating current of your system is 14A. If calculated with a 2mR sampling resistor, it is very likely to trigger the inductor peak current limit. In addition, there is also a problem with the selection of MOS tubes. The driving voltage of SC8002 is 5.2V. It is recommended to choose a Mosfet with a junction capacitance of less than 1500pF. The G90N04 you chose (searched GOFORD for the same model of MOS), the typical junction capacitance is 5000pF. According to the schematic diagram, the two parallel connections have a total junction capacitance of 10nF. Insufficient driving capability is another important reason for load abnormality. It is recommended to replace SC8001 for this design. The driving voltage of SC8001 is 10V, which has stronger driving capability and eliminates the limitation on inductor current, making it more suitable for your application.

liushiming82

It turns out that this chip has so much hidden information. But SC8001 comes with a battery. I want one without a battery and with a constant current source.

qiushenghua

liushiming82 posted on 2019-4-3 15:04 It turns out that this chip has so much hidden information, but SC8001 comes with a battery. I want one without a battery and with a constant current source

SC8001 does not come with a battery. . . It only has a unidirectional Buck, and the input can be current-limited, and the output can be current-limited. Did you mistake it for SC8801? Send me a private message with the company information, product form, and estimated annual usage, and I will send you a sample.

liushiming82

qiushenghua posted on 2019-4-3 17:47 SC8001 does not come with a battery. It only has a unidirectional Buck, and the input can be current limited, and the output can be current limited. Did you mistake it for SC8801? ...

Bro, can you add my QQ number? My number is 340150293

liushiming82

Is there any chip with battery that you would recommend?

xxh2003

qiushenghua posted on 2019-4-3 17:47 SC8001 does not come with a battery. It only has a unidirectional Buck, and the input can be current limited, and the output can be current limited. Did you mistake it for SC8801? ...

Hello, I also want to use this SC8001, hope to get your support!

le062

major!