CR2032電池的應用中如何避免VDD跌落?
CR2032電流供應能力較低,因此當需要較大的瞬間電流時(例如連接Load cell瞬間),往往會造成VDD的瞬間跌落, SN8P1917與SN8P1919芯片中,可利用以下方式避免上述情形産生:
(a). 在啓動Charge pump時先將CPCKS設定到最慢,延遲200ms再將CPCKS設定到建議值，例如：
xb0mov cpm,a ;acmenb,avddrenb,avesel,avenb,cpsts,cpauto,cpon,cprenb
mov a,#20 ;delay 300ms
call delay
mov a, #00000100b
xb0mov cpcks, a ;set cpcks as 15.6k clock.
mov a,#3
call delay
(b). 順序啓動AVDDR/ACM/AVE+,避免同時啓動三個電壓輸出.
穩定時間建議表如下: (以SN8P1919爲例)
Delay Time:
(a). 在啓動Charge pump時先將CPCKS設定到最慢,延遲200ms再將CPCKS設定到建議值，例如：
xb0mov cpm,a ;acmenb,avddrenb,avesel,avenb,cpsts,cpauto,cpon,cprenb
mov a,#20 ;delay 300ms
call delay
mov a, #00000100b
xb0mov cpcks, a ;set cpcks as 15.6k clock.
mov a,#3
call delay
(b). 順序啓動AVDDR/ACM/AVE+,避免同時啓動三個電壓輸出.
穩定時間建議表如下: (以SN8P1919爲例)
Delay Time:
| Power Type | Charge Pump Enable Delay | Enable ACM | Enable AVDDR | Enable AVE+ | |
| Step 1 CPCKS=#00001011B | Step 2 CPCKS=#00000100B | ||||
| CR2032 (2.4~3V) | 200ms | 100ms | 5ms | 50ms | 50ms |
| CR2032 ((4.4~6V)) | - | - | 5ms | 50ms | 50ms |
| AA/AAA Bat.(2.4~3V) | 100ms | 50ms | 5ms | 50ms | 50ms |
| AA/AAA Bat.(4.4~6V) | - | - | 5ms | 50ms | 50ms |
| External 5V Reg. | - | - | 5ms | 50ms | 50ms |
詳細參考文件: SN8P1900系列Datasheet