Service manual

UX-B20U/UX-B20C/B25C
5 – 14
2.7. IC10 (PLCC44) Hardware description
This specfication describes a multifunction analog ASIC to be used in
inkjet printer applications. This ASIC integrates two Switching Voltage
Regulator circuits, two motor drive circuits and a Reset circuit in a sin-
gle IC.
The functions implemented are:
• Two DC-to-DC converters providing the following voltages from an
unregulator input of +21 volts to +42 volts DC:
• VCC Voltage Regulator circuit - A buck type switching regulator
using a MOSFET (internal to the ASIC), current sense resistor
(internal to the ASIC), Schottky diode (external to the ASIC),
external inductor and filter capacitor. This converter shall be
programmable to provide either +3.3 volts, +5 volts, +5%/-4%,
at a current of 10ma.(min.) to 500 ma.(max./ave.).
• VPH Voltage Regulator circuit - A buck type switching regulator
using a MOSFET (internal to the ASIC), current sense resistor
(internal to the ASIC), Schottky diode (external to the ASIC),
external inductor and filter capacitor. This converter is to have a
programmable output voltage (by means of an external resistor
divider network) in the range of +10 volts to +15 volts, +/2% with
a VBULK input voltage range of +21 volts to +42 volts. With
VPH = +11.75 volts the load current is 10 ma.(min.), 1amp.
(max./ave.) with a peak of 1300 ma. (peak/ave.) for 400 ms. The
VPH regulator shall have a ENABLE bit in the serial register that
allows software to turn on and off this converter.
• The ENABLE bit when set low shall place this ASIC into its low-
est stand-by power mode in order to minimize idle power. The
VCC regulator is not effected by ENABLE bit.
• Two Motor Drivers:
• Both Motor Drivers are to be selectable as EITHER a bidirection
DC motor driver with PWM control with peak currents of 2.0
amps and RMS currents of TBD mA or a Bipolar stepper motor
driver with current levels (average) of 183 ma., 367 ma. and 550
ma. per phase with quarter step mode capability. In stepper
mode both drivers shall be capable of being operated in the
quarter step mode.
• nRESET Generation
All ASIC input control lines are to be compatible with CMOS type +3.3
volts and +5 volts logic.
PLCC44 (IC10) Pin descriptions
PIN
NO.
PIN NAME PIN DESCRPTION
1 VCP (Capacitor VBULK)
2 CP2 (Capacitor to CP1)
3 CP1 (Capacitor to CP2)
4 nRESET Reset Port
5 VCC VCC Supply Voltage
6 GND Substrate Ground
7 GND Substrate Ground
8 VCC_FB VCC Regulator Feedback Input
9 MD1_MODE Mode Select for Motor Driver MD1
10 VCC_SOURCE Source of internal MOSFET for VCC
Regulator
11 VBULK VBULK Supply Voltage
12 MD2_OUT_A+ MD2-Motor Driver Output a Plus
13 MD_R_SENSE_A MD2-Output A Current Sense Resistor
14 MD2_OUT_A- MD2-Motor Driver Output A Minus
15 VBULK VBULK Supply Voltage
16 VBULK VBULK Supply Voltage
17 GND Substrate Ground
18 GND Substrate Ground
19 MD1_OUT_A+ MD!-MOtor Driver Output A Plus
20 MD1_R_SENSE_A MD1-Output A Current Sense Resistor
21 MD1_OUT_A- MD1-Motor Driver Output A Minus
22 MD1_DCM_PWM MD1_DC Motor Driver PWM Input
23 VBULK VBULK Supply Voltage
24 MD2_DCM_PWM MD2-DC Motor Driver PWM Input
25 MD1_OUT_B- MD1-Motor Driver Output B Minus
26 MD1_R_SENSE_B MD1-Output B Current Sense
27 MD1_OUT_B+ MD1-Motor Driver Output B Plus
28 GND Substrate Ground
29 GND Substrate Ground
30 VBULK VBULK Supply Voltage
31 VBULK VBULK Supply Voltage
32 MD2_OUT_B- MD2-Motor Driver Output B Minus
33 MD2_R_SENSE_B MD2-Output B Current Sense Resistor
34 MD2_OUT_B+ MD2-Motor Driver Output B Plus
35 VBULK VBULK Supply Voltage
36 VPH_SOURCE Source of internal MOSFET for VPH
Regulator
37 MD2_MODE Mode Select for Motor Driver MD2
38 VPH_FB VPH Regulator Feedback Input
39 GND Substrate Ground
40 GND Substrate Ground
41 SDI Serial Port Data Input
42 SCLK Serial Port Clock
43 nCS Serial Port Chip Select
44 AGND Analog Ground