AK4184A Datasheet, PDF (28/36 Pages) Asahi Kasei Microsystems – TSC with Keypad Scanner and GPIO Expander

[AK4184A]
■ LED ً౓ௐ੔ճ࿏
AK4184A ͸ɺന৭ LED ً౓ௐ੔Λߦ͏ PWM ํࣜͷௐޫճ࿏ৼൃͼٴճ࿏(OSC)Λ಺ଂ͍ͯ͠·͢ɻLED ͷ
ௐޫ͸ɺLED υϥΠό IC ΁ͷ PWM ೖྗप೾਺(f_PWM)ͱ duty Λมߋ͢ΔࣄͰߦ͍·͢ɻPWM ޚ੍ճ࿏͸಺
ଂͷൃৼثͷग़ྗΛ෼पͯ͠ɺεΠονϯάಈ࡞Λߦ͍·͢ɻPWM ൃৼप೾਺(fpwm)Ϩϯδ͸ɺ࠷খ 80Hz
(typ.)͔ΒՄೳͰ͢ɻجຊ೾ fpwm ΛϩδοΫ੍ޚճ࿏Ͱ 32 εςοϓͷσϡʔςΟλΠϛϯάͰग़ྗ͠·͢ɻ
ग़ྗ͸ɺPACT bit Ͱ੾Γସ͑·͢ɻBRV bitɺDIV bit Ͱ PWM प೾਺ͷ duty ෯Λઃఆ͠·͢ɻϊʔϚϧϞʔ
υͰσϡʔςΟσʔλ͕มߋ͞ΕΔ·Ͱ࿈ଓͰग़ྗ͞Ε·͢ɻ
ग़ྗͷϑϧεέʔϧ͸ɺIOVDD τϥοΩϯάͷ CMOS ग़ྗͱΦʔϓϯυϨΠϯग़ྗΛબ୒͢Δ͜ͱ͕Մೳ
Ͱ͢ɻϦηοτղআޙͷॳظ஋͸ɺൃৼճ࿏͸ύϫʔμ΢ϯঢ়ଶͰ BRCONT pin ͸ “L”Λग़ྗ͠·͢ɻ
Oscillator ^fosc Divider
2^(DIV[2:0]+7)
f_{pwm PWM Logic} f_brcont
Controller
BRCONT pin
Figure 16. PWM output block
Example BRV [4:0] =11H ઃఆ࣌
಺෦ PWM
Χ΢ϯλ
0 12
3 8 9 10 11 12 13 14 15 16 17 18 8 24 25 26 27 28 29 30 31 0
PWM प೾਺(fpwm) = fosc / 2^(DIV[2:0]+7)
BRCONT
Duty Cycle BRV[4:0] =11H
Figure 17. PWM output waveform
■ PWM Control Register (PAGE 1)
Addr Name
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0
MSB
LSB
18H PWMCTRL LPU 0 0
BRV[4:0]
0 PACT 0 0 0
DIV[2:0]
Table 35. PWM Control Register Format
Bits
15
14:13
12:8
7
6
5:3
2:0
Name
LPU
BRV
PACT
DIV
Description
Output type Open drain/ CMOS
0: CMOS type (default)
1: Open Drain type
Reserved
Bright Control Value
The period of “H” output level is (control value + 1) cycle in unit of (fpwm/32)
Reserved
Oscillator and PWM Logic Controller Power Up
0: Power Down State (default)
1: Normal mode (Oscillator power up and enable output)
Reserved
PWM clock divider index
fpwm(typ.) = fosc/2 [DIV + 7]
Table 36. PWM Control Register
MS0947-J-00
-28-
2008/04