Minilogic ML1538 4-ch motor driver for portable cd player Datasheet

ML1538
_______________________________________________________________
ML1538 4-ch Motor Driver for Portable CD players
™ Application
™ Features
‹ Portable CD player
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Built-in 4ch H bridge driver, and PWM control
of load drive voltage is made possible by
external components.
DC-DC converter control circuit on chip.
With inverted reset output pin.
Empty detection level can be switched between
rechargeable battery and dry battery.
Constant current charging; amount of current
can be varied by external resistor.
Built-in power transistor for charging.
Built-in independent thermal shutdown circuit
Package : QFP-44
™ General Description
ML1538 driver IC contains a 4ch H bridge driver and DC-DC converter control circuit, and was
developed for portable CD players. The package in use is QFP-44, making it ideal for smaller set.
4ch Motor Driver for Portable CD Player
March, 2004 V1.0
1/17
ML1538
_______________________________________________________________
™ Block Diagram
RCHG
OUT1R
33
32
OUT1F OUT2R
31
OUT2F POWGND OUT3F
30
29
28
OUT3R
OUT4F
26
25
27
OUT4R BRAKE1
24
23
BRAKE1
EMP
35
HV CC
36
PSW
37
CLK
38
START
39
OFF
40
CHGVCC
41
22 IN1
MUTE2
34
BTL
BTL
BTL
BTL
TSD
MAXIMUM
DETECTION
POWER OFF
STARTER
+ -
21 MUTE2
20 IN2
MUTE34
AMUTE
V
/
I
+
V
/
I
+
18 IN4
V
/
I
+
17 IN3
V
/
I
+
16 Vref
19 MUTE34
Pre-Driver Pow er Supply
SEL
42
PREGND
43
15 VSYS2
TRIANGLE-WAVE
14 OP+
+
-
44
Power Unit
Power Supply
PWMFIL
OVER-VOLTAGE
TSD
+
+ -
13 OPOUT
12 VSYS1
+ + +-
Control Circuit
Pow er Supply
+ -
1
2
3
4
5
6
7
8
9
10
11
BSEN
BATT
RESET
DEAD
SW
EO
EI
SPRT
CT
N.C.
OP-
4ch Motor Driver for Portable CD Player
March, 2004 V1.0
2/17
ML1538
_______________________________________________________________
™ Pin Configuration
RCHG
OUT1R
33
32
OUT1F OUT2R
31
OUT2F POWGND OUT3F OUT3R
30
29
28
27
OUT4F
26
25
OUT4R BRAKE1
24
23
AMUTE
34
22 IN1
EMP
35
21 MUTE2
HV CC
36
20 IN2
PSW
37
19 MUTE34
CLK
38
18 IN4
START
39
OFF
40
16 Vref
CHGVCC
41
15 VSYS2
SEL
42
14 OP+
PREGND
43
13 OPOUT
PWMFIL
44
12 VSYS1
ML1538
17 IN3
1
2
3
4
5
6
7
8
9
10
11
BSEN
BATT
RESET
DEAD
SW
EO
EI
SPRT
CT
N.C.
OP-
Pin
Pin Name
Pin
Pin Name
Pin
Pin Name
Pin
Pin Name
1
BSEN
12
VSYS1
23
BRAKE1
34
AMUTE
2
BATT
13
OPOUT
24
OUT4R
35
EMP
3
RESET
14
OP+
25
OUT4F
36
HVCC
4
DEAD
15
VSYS2
26
OUT3R
37
PSW
5
SW
16
Vref
27
OUT3F
38
CLK
6
EO
17
IN3
28
POWGND
39
START
7
EI
18
IN4
29
OUT2F
40
OFF
8
SPRT
19
MUTE34
30
OUT2R
41
CHGVCC
9
CT
20
IN2
31
OUT1F
42
SEL
10
N.C.
21
MUTE2
32
OUT1R
43
PREGND
11
OP-
22
IN1
33
RCHG
44
PWMFIL
4ch Motor Driver for Portable CD Player
March, 2004 V1.0
3/17
ML1538
_______________________________________________________________
™ Pin Description
Pin No.
Pin Name
I/O
Function
Internal Equivalent Circuit
1
BSEN
Input
Battery Voltage Monitor
2
BATT
Input
Battery Power Supply Input
3
RESET
Output Reset Detect Output
4
DEAD
Input
5
SW
Output Transistor Drive For Voltage
Multiplier
6
EO
Output Error Amplifier Output
Power Supply
DEAD Time Setting
4ch Motor Driver for Portable CD Player
March, 2004 V1.0
4/17
ML1538
_______________________________________________________________
Pin No.
Pin Name
I/O
Function
Internal Equivalent Circuit
7
EI
Input
Error Amplifier Input
8
SPRT
Output Short Circuit Protection
Setting
9
CT
Output Triangular-Wave Output
10
N.C.
11
14
OPOP+
Input
Op Amp Negative Input
Op Amp Positive Input
12
VSYS1
Input
Control Circuit Power Supply
Input
13
OPOUT
Output Op Amp Output
4ch Motor Driver for Portable CD Player
Control Circuit Power Supply
March, 2004 V1.0
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ML1538
_______________________________________________________________
Pin No. Pin Name
I/O
Function
Internal Equivalent Circuit
15
VSYS2
Input
Driver Pre-step Power Supply Pre-Drive Power Supply
16
Vref
Input
Reference Voltage Input
17
18
20
IN3
IN4
IN2
Input
CH3 Control Signal Input
CH4 Control Signal Input
CH2 Control Signal Input
22
IN1
19
21
23
MUT34
MUT2
BRAKE1
Input
24
25
26
27
29
30
31
32
OUT4R
OUT4F
OUT3R
OUT3F
OUT2F
OUT2R
OUT1F
OUT1R
Output CH4 Negative Output
CH4 Positive Output
CH3 Negative Output
CH3 Positive Output
CH2 Positive Output
CH2 Negative Output
CH1 Positive Output
CH1 Negative Output
28
POWGND
36
HVCC
CH1 Control Signal Input
CH3 and 4 Mute
CH2 Mute
CH1 Brake
Power Block Power Supply
Ground
Input
H-Bridge Power Supply Input
4ch Motor Driver for Portable CD Player
March, 2004 V1.0
6/17
ML1538
_______________________________________________________________
Pin No.
Pin Name
I/O
Function
Internal Equivalent Circuit
33
RCHG
Input
Charge Current Setting
34
AMUTE
Output Reset Invert Output
35
EMP
Output Empty Detect Output
37
PSW
Output PWM Transistor Drive
38
CLK
Input
External Clock Synchronizing
Input
4ch Motor Driver for Portable CD Player
March, 2004 V1.0
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ML1538
_______________________________________________________________
Pin No.
Pin Name
I/O
Function
Internal Equivalent Circuit
39
START
Input
Voltage Multiplier DC-DC
Converter Start
40
OFF
Input
Voltage Multiplier DC-DC
Converter OFF
41
CHGVCC
Input
Charging Circuit Power
Supply Input
42
SEL
Input
Empty Detect Level Switch
Output
43
PREGND
44
PWMFIL
Pre Section Power Supply
Input
Charging Circuit Power Supply
Pre Section Power Supply Ground
PWM Phase Compensation
* The positive and negative outputs are the polarity with respect to the input
4ch Motor Driver for Portable CD Player
March, 2004 V1.0
8/17
ML1538
_______________________________________________________________
™ Absolute Maximum Ratings
Item
Symbol
Rating
VCC *1
13.5
Supply Voltage
IO
500
Driver Output Current
Pd
625 *2
Power Dissipation
TOPR
-30 ~ +85
Operating Temperature
TSTG
-55 ~ +150
Storage Temperature
*1 Vcc shows input voltage of VSYS1, VSYS2, HVCC, BATT, and CHGVCC.
*2 Reduced by 5mW for each increase in Ta of 1°C over 25°C
Unit
V
mA
mW
°C
°C
™ Recommended Operating Conditions
Item
Control Circuit Power Supply Voltage
Pre-Driver Circuit Power Supply Voltage
H-Bridge Power Supply Voltage
Power Supply Voltage
Charging Circuit Power Supply Voltage
Operating Temperature
Symbol
VSYS1
VSYS2
HVcc
BATT
CHGVcc
Ta
Min.
2.7
2.7
1.5
3.0
-10
Typ.
3.2
3.2
PWM
2.4
4.5
25
Max.
5.5
5.5
BATT
8.0
8.0
70
Unit
V
V
V
V
V
°C
™ Electrical Characteristics
(unless otherwise specified, Ta=25°C, BATT=2.4V, VSYS1=VSYS2=3.2V, Vref=1.6V, CHGVcc=0V, fCLK=88.2kHz)
Item
Symbol
Measurement Conditions
Min.
Typ.
Max.
< Common Section >
BATT Stand-by Current
IST
BATT=9.0V,
0
3
VSYS1=VSYS2=Vref=0V
BATT Supply Current (No load)
IBAT
HVcc=0.45V, MUTE34=3.2V
2.5
4.0
VSYS1 Supply Current (No load)
ISYS1
HVcc=0.45V, MUTE34=3.2V, EI=0V
4.7
6.4
VSYS2 Supply Current (No load)
ISYS2
HVcc=0.45V, MUTE34=3.2V
4.1
5.5
CHGVcc Supply Current (No load)
ICGVCC
CHGVcc=4.5V, ROUT=OPEN
0.65
2.00
< H-Bridge Driver Part >
Voltage Gain ch1, ch3.ch4
GVC134
12
14
16
Voltage Gain ch2
GVC2
21.5
23.5
24.5
-2
0
2
Gain Error By Polarity
⊿GVC
Input pin resistance ch1,ch3,ch4
RIN134
IN=1.7V and 1.8V
9
11
13
Input pin resistance ch2
RIN2
IN=1.7V and 1.8V
6
7.5
9
Maximum Output Voltage
VOUT
1.9
2.1
RL=8Ω, HVcc=BATT=4.0V,
IN=0-3.2V
Saturation Voltage (Lower)
VsatL
Io=-300mA, IN=0 and 3.2V
240
400
Saturation Voltage (Upper)
VsatU
Io=-300mA, IN=0 and 3.2V
240
400
Input Offset Voltage
VOI
-8
0
8
Outut Offset Voltage ch1,ch3,ch4
VOO134
Vref=IN=1.6V
-50
0
50
Output Offset Voltage ch2
VOO2
Vref=IN=1.6V
-130
0
130
Dead Zone
VDB
-10
0
10
BRAKE1ON Threshold Voltage
VBRON
IN1=1.8V
2.0
BRAKE1OFF Threshold Voltage
VBROFF
IN1=1.8V
0.8
MUTE2 ON Threshold Voltage
VM2ON
IN2=1.8V
2.0
4ch Motor Driver for Portable CD Player
Unit
µA
mA
mA
mA
mA
dB
dB
dB
kΩ
kΩ
V
mV
mV
mV
mV
mV
mV
V
V
V
March, 2004 V1.0
9/17
ML1538
_______________________________________________________________
™ Electrical Characteristics
(unless otherwise specified, Ta=25°C, BATT=2.4V, VSYS1=VSYS2=3.2V, Vref=1.6V, CHGVcc=0V, fCLK=88.2kHz)
Item
Symbol
Measurement Conditions
Min.
Typ.
Max.
< H-Bridge Driver Part >
MUTE2 OFF Threshold Voltage
VM2OFF
IN2=1.8V
0.8
MUTE34 ON Threshold Voltage
VM34ON
IN3=IN4=1.8V
0.8
MUTE34 OFF Threshold Voltage
VM34OFF
IN3=IN4=1.8V
2.0
Vref ON Threshold Voltage
VrefON
IN1=IN2=IN3=IN4=1.8V
1.2
Vref OFF Threshold Voltage
VrefOFF
IN1=IN2=IN3=IN4=1.8V
0.8
BRAKE1 Brake Current
IBRAKE1
Current difference between BRAKE
4
7
10
pin "H" time and "L" time.
< PWM Power Supply Driving >
PSW Sink Current
IPSW
IN1=2.1V
10
13
17
HVcc Level Shift Voltage
VSHIF
IN1=1.8V, HVcc-OUT1F
0.35
0.45
0.55
HVcc Leak Current
IHLK
HVcc=9.0V,
0
5
VSYS1=VSYS2=BATT=0V
PWM Amp Transfer Gain
GPWM
IN1=1.8V, HVcc=1.2~1.4V
1/60
1/50
1/40
< DC-DC Converter >
< Error Amp >
VSYS1 Threshold Voltage
VS1TH
3.05
3.20
3.35
EO Pin Output Voltage "H"
VEOH
1.4
1.6
EI=0.7V, Io=-100µA
EO Pin Output Voltage "L"
VEOL
0.3
EI=1.3V, Io=100µA
< Short Circuit Protection >
SPRT Pin Voltage
VSPR
EI=1.3V
0
0.1
EO=H SPRT Pin Current1
ISPR1
EI=0.7V
6
10
16
OFF=L SPRT Pin Current2
ISPR2
EI=1.3V, OFF=0V
12
20
32
SPRT Pin Current3 Over-Voltage
ISPR3
EI=1.3V, BATT=9.5V
12
20
32
SPRT Pin Impedance
RSPR
175
220
265
SPRT Pin Threshold Voltage
VSPTH
EI=0.7V, CT=0V
1.10
1.20
1.30
Over-Voltage Protection Detect
VHVPR
BSEN Pin Voltage
8.0
8.4
9.0
< Transistor Driving >
BATT= CT =1.5V,
VSYS1=VSYS2=0V,
0.78
0.98
1.13
SW Pin Output Voltage1 "H"
VSW1H
IO=-2mA Starting Time
SW Pin Output Voltage 2 "H"
VSW2H
CT =0V, IO=-10mA, EI=0.7V,
1.00
1.50
SPRT=0V
SW Pin Output Voltage 2 "L"
VSW2L
CT =2.0V, IO=10mA
0.30
0.45
SW Pin Oscillating Frequency1
fSW1
CT =470pF, VSYS1=VSYS2=0V
65
80
95
Starting Time
SW Pin Oscillating Frequency2
fSW2
CT =470pF, CLK=0mA
60
70
82
SW Pin Oscillating Frequency3
fSW3
CT =470pF
88.2
SW Pin Minimum Pulse Width
TSWmin
CT =470pF, EO=0.5V Æ 0.7V Sweep
0.01
0.60
Pulse Duty Start
DSW1
CT =470pF, VSYS1=VSYS2=0V
40
50
60
Max.Pulse Duty At Self-Running
DSW2
CT =470pF, EI=0.7V, CLK=0V
70
80
90
Max.Pulse Duty At CLK
DSW3
CT =470pF, EI=0.7V
65
75
85
Synchronization
4ch Motor Driver for Portable CD Player
Unit
V
V
V
V
V
mA
mA
V
µA
1/kΩ
V
V
V
V
µA
µA
µA
kΩ
V
V
V
V
V
kHz
kHz
kHz
µs
%
%
%
March, 2004 V1.0
10/17
ML1538
_______________________________________________________________
™ Electrical Characteristics
(unless otherwise specified, Ta=25°C, BATT=2.4V, VSYS1=VSYS2=3.2V, Vref=1.6V, CHGVcc=0V, fCLK=88.2kHz)
Item
Symbol
Measurement Conditions
Min.
Typ.
Max.
Unit
< Interface >
VSYS1
V
OFF Pin Threshold Voltage
VOFTH
EI=1.3V
- 2.0
OFF Pin Bias Current
START Pin ON Threshold
Voltage
START Pin OFF Threshold
Voltage
IOFF
VSATH1
OFF=0V
VSYS1=VSYS2=0V, CT =2.0V
75
VSATH2
VSYS1=VSYS2=0V, CT =2.0V
START Pin Bias Current
ISTART
START=0V
BATT
-0.3
10
13
2.0
CLK Pin Threshold Voltage "H"
CLK Pin Threshold Voltage "L"
CLK Pin Bias Current
< Dead Time >
DEAD Pin Impedance
DEAD Pin Output Voltage
< Starter Circuit >
Starter Switching Voltage
Starter Switching Hysteresis
Width
Discharge Release
< Empty Detection >
EMP Detection Voltage 1
EMP Detection Voltage 2
EMP Detection Hysteresis
Voltage1
EMP Detection Hysteresis
Voltage2
EMP Pin Output Voltage
EMP Pin Output Leak Current
BSEN Pin Input Resistance
BSEN Pin Leak Current
SEL Pin Detection Voltage
SEL Pin Detection Current
< Reset Circuit >
VSYS1 RESET Threshold
Voltage Ratio
RESET Detection Hysteresis
Width
RESET Pin Output Voltage
RESET Pin Pull Up Resistance
AMUTE Pin Output Voltage 1
VCLKTHH
VCLKTHL
ICLK
VSYS1=VSYS2=0VÆ3.2V, START=0V
START=0V
VDIS
115
BATT
-1.0
µA
V
V
20
16
CLK=3.2V
RDEAD
VDEAD
VSTNM
VSNHS
95
30
19
µA
0.8
10
V
V
µA
52
0.78
65
0.88
78
0.98
kΩ
V
2.3
130
2.5
200
2.7
300
V
mV
1.63
1.83
2.03
V
VEMPT1
VEMPT2
VEMHS1
VSEL=0V
ISEL=-2µA
VSEL=0V
2.1
1.7
25
2.2
1.8
50
2.3
1.9
100
V
V
mV
VEMHS2
ISEL=-2µA
25
50
100
mV
VEMP
IEMPL
RBSEN
IBSENL
VSELTH
ISELT
Io=1mA, BSEN=1V
BSEN=2.4V
VSEL=0V
VSYS1=VSYS2=0V, BSEN=4.5V
VSELTH=BATT-SEL, BSEN=2.0V
0.5
1.0
27
1.0
V
µA
kΩ
µA
V
µA
HSRT
Comparison with error amplifier
threshold voltage
VRSTHS
VRST
RRST
VAMT1
AMUTE Pin Output Voltage 2
VAMT2
AMUTE Pin Pull DOWN
Resistance
RAMT
17
23
1.5
-2
85
90
95
%
25
50
100
mV
72
BATT
-04
BATT
-04
77
90
0.5
108
BATT
V
kΩ
V
BATT
V
113
kΩ
Io=1mA, VSYS1=VSYS2=2.8V
Io=-1mA, VSYS1=VSYS2=2.8V
Io =-1mA, START=0V,
VSYS1=VSYS2=0V
4ch Motor Driver for Portable CD Player
95
March, 2004 V1.0
11/17
ML1538
_______________________________________________________________
™ Electrical Characteristics
(unless otherwise specified, Ta=25°C, BATT=2.4V, VSYS1=VSYS2=3.2V, Vref=1.6V, CHGVcc=0V, fCLK=88.2kHz)
Item
Symbol
Measurement Conditions
Min.
Typ.
Max.
< Op Amp >
Input Bias Current
IBIAS
OP+=1.6V
300
Input Offset Voltage
VOIOP
-5.5
0
5.5
High Level Output Voltage
VOHOP
RL=OPEN
2.8
Low Level Output Voltage
VOLOP
RL=OPEN
0.2
Output Drive Current (Source)
ISOU
-6.5
-3.0
50Ω GND
Output Drive Current (Sink)
ISIN
0.4
0.7
50Ω VSYS1
Open Loop Voltage Gain
GVO
VIN=-75dBV, f=1kHz
70
Slew Rate
SR
0.5
< Battery Charging Circuit >
RCHG Pin Bias Voltage
VRCHG
0.71
0.81
0.91
CHGVcc=4.5V, RCHG=1.8 kΩ
RCHG Pin Output Resistance
RRCHG
CHGVcc=4.5V, RCHG=0.5 and 0.6V
0.75
0.95
1.2
SEL Pin Leak Current 1
ISELLK1
CHGVcc=4.5V, RCHG=OPEN,
1.0
BATT=4.5V
SEL Pin Leak Current 2
ISELLK2
1.0
CHGVcc=0.6V, RCHG=1.8 kΩ,
BATT=4.5V
SEL Pin Saturation Voltage
VSELCG
0.45
1.00
CHGVcc=4.5V, Io=300mA, RCHG=0kΩ
4ch Motor Driver for Portable CD Player
Unit
nA
mV
V
V
mA
mA
dB
V/µs
V
kΩ
µA
µA
V
March, 2004 V1.0
12/17
ML1538
_______________________________________________________________
™ Application Circuit
M
M
Transverse
Focus
Spindle
Tracking
27
26
BRAKE1
26
OUT4R
27
OUT4F
28
OUT3R
29
OUT3F
30
POWGND
31
OUT2F
OUT2R
32
OUT1F
33
OUT1R
RCHG
1.8k
23
BRAKE1
AMUTE
IN1
34
22
MUTE2
EMP
35
HVCC
47u
0.1u
+
BTL
36
BTL
BTL
PSW
CLK
MAXIMUM
DETECTION
38
START
POWER OFF
STARTER
+ -
39
0.1u
OFF
100k
40
CHGVCC
41
+
V
/
I
+
18
V
/
I
+
17
V
/
I
+
16
19
IN4
IN3
Vref
VSYS2
15
TRIANGLE-WAVE
OP+
SEL
42
14
PREGND
OPOUT
+
-
43
+
+ -
13
PWMFIL
VSYS1
Power Unit
Power Supply
Control Circuit
Pow er Supply
+
47u
DC-DC
Converter
Circuit
8
0.022u
0.1u
9
10
OP-
7
8.2k
0.1u
VIN
6
N.C.
5
SPRT
4
CT
+ EI
3
DEAD
2
RESET
1
BATT
BSEN
470p
+ +-
SW
100k
12
+ -
EO
44
2200p
MUTE34
V
/
I
Pre-Driver Pow er Supply
OVER-VOLTAGE
TSD
IN2
20
TSD
37
47
BTL
MUTE34
33u
MUTE2
21
11
Filter
470p
VOUT
+
100u
Note : We shall not be liable for any trouble or damage caused by using this circuit.
4ch Motor Driver for Portable CD Player
March, 2004 V1.0
13/17
ML1538
_______________________________________________________________
™ Circuit Operation
1. H-bridge driver block
(1) Gain setting
The driver input resistance (ch 1,3 and 4) are 11kΩ typ., ch2 is 7.5 kΩ typ. . Set the gain according to the
following formula.
ch1
ch2
55k
GV=20log
11k+R
(db)
ch3
ch2
GV=20log
110k
7.5k+R
(db)
R: Externally-connected input
The driver output stage power supply is HVCC(PIN 36), and the bridge circuit power supply is VSYS2(PIN 15).
Connect a bypass capacitor between these two power supplies (approximately 0.1µF).
(2) Mute function
Of the four drivers, ch1 has a brake function, and the other channels have a mute function.
When BRAKE1(PIN 23) is set to high level, both ch1 outputs go low level, and the circuit enters brake mode.
When MUTE2(PIN 21) is set to high level, the ch2 output is muted.
When MUTE34(PIN 19) is set to high level, the ch3 and 4 outputs are muted.
(3) Vref drop mute
When the voltage applied to Vref(PIN16) is 1.0V or less typ., the driver outputs are set to high impedance.
(4) Thermal shutdown
When the chip temperature reaches 150°C typ., the output current is cut. The chip starts operating again at
about 120°C typ. .
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2. PWM power supply drive block
This detects the maximum output level from among the four channels, and supplies the load drive power supply
(PIN 36) for the PWM. The external components are a PNP transistor, coil, Schottky diode, and capacitor.
3. DC-DC converter block
(1) Output voltage
3.2V typ. Voltage multiplier circuit can be constructed using external components. This voltage can be varied
with the addition of an external resistor. The setting method is as follows.
VSYS1=1.2 x
R1· R3 +
R1+R3
R2· R4
R2+R4
(V)
R2· R4
R2+R4
R1 = external resistor
R2 = external resistor
R3 = 35 kΩ
R4 = 21 kΩ
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(2) Short protect function
When the error amplifier output(PIN 6) has switched to the high-level state, SPRT(PIN 8) is charged, and when
the voltage reaches 1.2V typ. , the SW(PIN 5) switching stops. The time until switching stops is set by the
capacitor connected to SPRT(PIN 8) according to the following formula.
t=CSPRT x
VTH (sec) (VTH=1.2V, ISPRT=10µA)
ISPRT
(3) Soft start function
The soft start function operates when a capacitor is connected between DEAD(PIN 4) and GND.
Also, the maximum duty can be varied by connecting a resistor to PIN 4.
t=CDEAD x R(sec) (R=65 kΩ)
(4) Power off function
When low-level is applied to OFF(PIN 40), SPRT(PIN 8) is charged, and when the voltage reaches 1.2V typ.,
the SW(PIN 5) switching stops. The time until switching stops is set by the capacitor connected to SPRT(PIN 8)
according to the following formula.
t=CSPRT
VTH
OFF
(sec) (VTH=1.2V, IOFF=20µA)
(5) Over voltage protection circuit
When the voltage applied to BSEN(PIN 1) reaches 8.4V typ., SPRT(PIN 8) is charged, and when the voltage
reaches 1.2V typ., the SW(PIN 5) switching stops. The time until switching stops is set by the capacitor
connected to SPRT(PIN 8) according to the following formula.
t=CSPRT x
VTH
OFF
(sec) (VTH=1.2V, IOFF=20µA)
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4. Empty detector block
(1) Output voltage
When the voltage applied to the BSEN(PIN 1) falls below the detector voltage, EMP(PIN 35) goes from high
level to low level (open-collector output). The detector voltage has 50mV typ. of hysteresis to prevent output
chattering. Use SEL(PIN 42) to switch the detection voltage as shown below.
SEL
Detect Voltage
Return Voltage
L
2.20V typ.
2.25V typ.
High-Z
1.80V typ.
1.85V typ.
5. Reset circuit block
At about 90% typ. Of the DC-DC converter output voltage, RESET(PIN 3) goes from low level to high
level, and AMUTE(PIN 34) goes from high level to low level. The reset voltage has 50mV typ. of
hysteresis to prevent output chattering.
6. Charging circuit block
The power supply for the charging circuit block is CHGVCC(PIN 41), and is independent from the other
circuits. The resistance between RCHG(PIN 33) and GND sets the charging current. This current is
drawn from SEL(PIN 42).
A thermal shutdown circuit is provided, and when the chip temperature reaches 150°C typ. the charging
current is cut. The chip starts operating again at about 120°C typ. .
The information presented in this document does not form part of any quotation or contract, is believed to be accurate and
reliable and may be changed without notice. No liability will be accepted by the publisher for any consequence of its use.
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