Epson LQ 1050 Technical Manual - Page 62

mitterarrentOf, omrEILO

Get Epson LQ 1050 - B/W Dot-matrix Printer PDF manuals and user guides View all Epson LQ 1050 manuals
Add to My Manuals
Save this manual to your list of manuals

Page 62 highlights

REV.-A 2.3.2.4 Chopper-Type Switching Regulator Circuit A chopper-type switching regulator is employed in the power supply circuit. Operation of the step-down circuit is as follows: -ton- .U , *Z / =ZZZ o i--~ t o Tr L f VI D c-: Vo< VL T o Figure 2-14. Step-Down Circuit Figure 2-14 shows the chopper-type, step-down switching regulator circuit. When the transistor is ON, voltage Vi is applied to coil L and capacitor C, and load current IL flows. At this time, electromagnetic energy WL is accumulated in choke coil L. When the transistor turns off, WL is applied to the load via flywheel diode D so that output voltage Vo becomes the average value: V. = Vi X Ton T where, T = Ton + Toff (T is constant) Therefore, Vo can be held constant by controlling Ton. Figure 2-15 shows the step down timings. Voltage between the collector and the emitter of Tr 'mit erarrentOf ;omrEILO+ *'ON "- Lo -V1-v-e lo- , Current at diode D when It is reverse recovered. (-' m-" cuwentdD Current"t'okecoi' oz2rEs'::F ILO = 10 - ( V1-vo)vo L 2Lt V 1 Figure 2-15. Step-Down Timings 2-18 ,.

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
  • 69
  • 70
  • 71
  • 72
  • 73
  • 74
  • 75
  • 76
  • 77
  • 78
  • 79
  • 80
  • 81
  • 82
  • 83
  • 84
  • 85
  • 86
  • 87
  • 88
  • 89
  • 90
  • 91
  • 92
  • 93
  • 94
  • 95
  • 96
  • 97
  • 98
  • 99
  • 100
  • 101
  • 102
  • 103
  • 104
  • 105
  • 106
  • 107
  • 108
  • 109
  • 110
  • 111
  • 112
  • 113
  • 114
  • 115
  • 116
  • 117
  • 118
  • 119
  • 120
  • 121
  • 122
  • 123
  • 124
  • 125
  • 126
  • 127
  • 128
  • 129
  • 130
  • 131
  • 132
  • 133
  • 134
  • 135
  • 136
  • 137
  • 138
  • 139
  • 140
  • 141
  • 142
  • 143
  • 144
  • 145
  • 146
  • 147
  • 148
  • 149
  • 150
  • 151
  • 152
  • 153
  • 154
  • 155
  • 156
  • 157
  • 158
  • 159
  • 160
  • 161
  • 162
  • 163
  • 164
  • 165
  • 166
  • 167
  • 168
  • 169
  • 170
  • 171
  • 172
  • 173
  • 174
  • 175
  • 176
  • 177
  • 178
  • 179
  • 180
  • 181
  • 182
  • 183
  • 184
  • 185
  • 186
  • 187
  • 188
  • 189
  • 190
  • 191
  • 192
  • 193
  • 194
  • 195
  • 196
  • 197
  • 198
  • 199
  • 200
  • 201
  • 202
  • 203
  • 204
  • 205
  • 206
  • 207
  • 208
  • 209
  • 210
  • 211
  • 212
  • 213
  • 214
  • 215
  • 216
  • 217
  • 218
  • 219
  • 220
  • 221
  • 222
  • 223
  • 224
  • 225
REV.-A
2.3.2.4 Chopper-Type Switching Regulator Circuit
A chopper-type switching regulator is employed in the power supply circuit. Operation of the step-down
circuit is as follows:
–ton—
.U
*Z=ZZZ
,
/
o
i—-~
t
o
Tr
f
L
VI
D
c-:
T
Vo<
VL
o
Figure 2-14. Step-Down Circuit
Figure 2-14 shows the chopper-type, step-down switching regulator circuit. When the transistor is ON,
voltage
Vi is applied to coil L and capacitor C, and load current IL flows. At this time, electromagnetic
energy WL is accumulated in choke coil L. When the transistor turns off, WL is applied to the load via
flywheel diode D so that output voltage Vo becomes the average value:
V.
=
Vi X Ton
T
where, T = Ton + Toff (T is constant)
Therefore, Vo can be held constant by controlling Ton. Figure 2-15
shows the step down timings.
Voltage between the collector
and the emitter of Tr
V1-ve
o
Lo
-
—
l—
,
Current at
diode
D
when It is reverse recovered.
(-’
‘mitterarrentOf
;omrEILO+
*’ON
“-
cuwentdD
m-”
Current”t’okecoi’
oz2rEs’::F
(
V1-vo)vo
L
ILO =
10
-
2Lt
V 1
Figure 2-15. Step-Down Timings
2-18
,.