M30218 Datasheet, PDF (136/179 Pages) Mitsubishi Electric Semiconductor – M30218 Group

Pull-down
Mitsubishi microcomputers
M30218 Group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Power Dissipation Calculating example 1
Fixed number depending on microcomputer’s standard
• VOH output fall voltage of high-breakdown port
2 V (max.); | Current value | = at 18 mA
• Resistor value 68 kΩ (min.)
• Power dissipation of internal circuit (CPU, ROM, RAM etc.) = 5 V X 38 mA = 190 mW
Fixed number depending on use condition
• Apply voltage to VEE pin: Vcc – 50 V
• Timing number 17; digit number 16; segment number 20
• Ratio of Toff time corresponding Tdisp time: 1/16
• Turn ON segment number during repeat cycle: 31
• All segment number during repeat cycle: 340 (= 17 X 20)
• Total number of built-in resistor: for digit; 16, for segment; 20
• Digit pin current value: 18 (mA)
• Segment pin current value: 3 (mA)
(1) Digit pin power dissipation
{18 X 16 X (1–1/16) X 2} / 17 = 31.77 mW
(2) Segment pin power dissipation
{3 X 31 X (1–1/16) X 2} / 17 = 10.26 mW
(3) Pull-down resistor power dissipation (digit)
(50 – 2)² /68 X (16 X 16/16) X (1 – 1/16) / 17 = 29.90 mW
(4) Pull-down resistor power dissipation (segment)
(50 – 2)² /68 X (31 X 20/20) X (1 – 1/16) / 17 = 57.93 mW
(5) Internal circuit power dissipation (CPU, ROM, RAM etc.) = 190.00 mW
(1) + (2)+ (3) + (4) + (5) = 319.86 mW
DIG0
DIG1
DIG2
DIG3
DIG13
DIG14
DIG15
Timing
number
12
3
Figure S-1. Digit timing waveform (1)
Repeat cycle
14 15 16 17
Tscan
135