w**t
发帖数: 592 | 1 电路:
sensor -> comparator(5v 几十uA)-> ?电路(提高驱动电流) ->负载
负载的输入电阻比较低，我的电路只能输出几十uA量级的电流。一旦连上负载电压
立刻从５v降到１v，什么电路可以加到中间提高输出驱动电流(只要能提高到几mA就好)？要求这个驱动电路只能用Vcc=５v。
试过BJT的emitter follower，我的电路甚至连基极都无法驱动。也试过FET,OP AMP的
voltage follower,输出电压都只是１v多点。还有什么别的办法？ | c****s
发帖数: 2487 | 2 参考一下class-D?
好)？要求这个驱动电路只能用Vcc=５v。
【在 w**t 的大作中提到】
: 电路:
: sensor -> comparator(5v 几十uA)-> ?电路(提高驱动电流) ->负载
: 负载的输入电阻比较低，我的电路只能输出几十uA量级的电流。一旦连上负载电压
: 立刻从５v降到１v，什么电路可以加到中间提高输出驱动电流(只要能提高到几mA就好)？要求这个驱动电路只能用Vcc=５v。
: 试过BJT的emitter follower，我的电路甚至连基极都无法驱动。也试过FET,OP AMP的
: voltage follower,输出电压都只是１v多点。还有什么别的办法？
| f*****0
发帖数: 489 | 3 the simplest solution is to use a few cmos gates (not gates or buffer) and
parallel them, 4049 (inverting) or 4050 (non-inverting) or the likes,
depending on your design. their max input current is typically less than 0.
1ua and in reality much much lower than that so they wouldn't overload your
comparator.
or you can use analog buffers (buf from ti for example). or use high output
current cfb / vfb opamps, either as buffers or as your comparator.
or you can use high current comparators, like lt | b*****e
发帖数: 1193 | | f*****0
发帖数: 489 | 5 ttl gates typically require input current of 20-40ua and can be as high as
150-200ua - they are essentially bjts.
in comparison, cmos gates need no more than 1ua and most times less than .
1ua |
|
