PWM STEP-UP DC/DC CONVERTER WITH VOLTAGE REGULATOR AND DETECTOR
RS5RM SERIES
APPLICATION MANUAL
NO.EA-018-0006
PWM STEP-UP DC/DC CONVERTER WITH VOLTAGE REGULATOR AND DETECTOR
RS5RM SERIES
OUTLINE
The RS5RM Series are step-up DC/DC converter ICs equipped with a voltage regulator (VR) and a voltage detector (VD) by CMOS process. Each of these step-up DC/DC converter ICs consists of a PWM DC/DC converter, a linear regulator and a voltage detector. These ICs are output-voltage-fixed type regulators which function as a linear regulator when input voltage is high, and as step-up DC/DC converter+linear regulator when input voltage is low, by using an inductor, a diode and a capacitor as external parts for the ICs. Since a voltage detector is built in these ICs, the potentials such as the output voltage of DC/DC converters can be monitored. In addition, these step-up DC/DC converter ICs are suitable for battery-powered and hand-held instruments because internal circuits can be turned off by the chip enable function so that the standby current can be minimized.
FEATURES
• Low Supply Current ..........................................TYP. 55µA (RS5RM3624A : VIN=3.0V,at no load) • Standby Mode.....................................................Istandby=MAX. 1.0µA (RS5RM ×××× A) Istandby=MAX. 10.0µA (RS5RM ×××× B) .......................Operating Voltage VIN=1.2V to 10V • Low Voltage Operation Possible • High Output Voltage Accuracy .........................Fixed Output Voltage Accuracy±2.5% • High Voltage Detection Accuracy .....................±2.5% • Output Voltage can be set at User's request (refer to Selection Guide). • Voltage close to battery's voltage can be output because these ICs are of a step-up / step-down type (Ex. a fixed voltage of 3V can be output by a 3V battery). • Soft Start Function, built-in Protection Circuits for Lx Driver • Phase Compensation Circuits built in • Pin for External Driver is equipped, and a large current output can be obtained. • Small Packages ..................................................8pin SOP
APPLICATIONS
• Power source for cameras, camcorders, and hand-held audio equipment. • Power source for small OA apparatus such as note book personal computers,and word processors. • Power source for hand-held communication appliances such as pagers,cordless telephones, and cellular phones.
1
RS5RM
BLOCK DIAGRAM
OSC VSS 1 PWM VLX Limiter 8 LX
CE
2
– +
7 Soft Start Vref1
EXT
VDOUT
3
+ – – +
6 Vref2
VDD
VDIN
4
5
VOUT
SELECTION GUIDE
In the RS5RM Series, the output voltage, the detector threshold, the version symbols, and the taping type for the ICs can be selected at the user's request. The selection can be made by designating the part number as shown below: RS5RM ××××× – ×× ← Part Number ↑ ↑↑ ↑ a bc d
} }
}
Code
Contens
a
Setting Output Voltage (VOUT): Stepwise setting with a step of 0.1V in the range of 1.5V to 6.0V is possible. Setting Detector Threshold (–VDET): Stepwise setting with a step of 0.1V in the range of 1.2V to 5.0V is possible. Designation of Version Symbols: A: Operation of all the internal circuits is stopped by setting CE pin at VDD level. B: Operation of only Step-up DC/DC converter is stopped by setting CE pin atVDD level. Designation of Taping Type: Ex. 8pin SOP : T1, T2 (refer to Taping Specification) “T2” is prescribed as a standard.
b
c
d
For example, the product with Output Voltage 5.0V, Detector Threshold 4.5V, Version A, and Taping Type T1, is designated by Part Number RS5RM5045A-T1.
2
RS5RM
PIN CONFIGURATION
• 8pin SOP
1 2 3 4
8 7 6 5
PIN DESCRIPTION
Pin No. Symbol Pin Description
1 2 3 4 5 6 7 8
VSS CE VDOUT VDIN VOUT VDD EXT LX
Ground Pin Chip Enable Pin Voltage Detector Output Pin.Nch Open Drain Output Detection Input Pin of Voltage Detector Output Pin for Regulator Step-up Output Pin.Power Supply Pin External Transistor Drive Pin External Inductor Drive Pin.
3
RS5RM
ABSOLUTE MAXIMUM RATINGS
Symbol Item Rating
Topt=25˚C,Vss=0V
Unit
VDD VLX VEXT VOUT VDOUT VCE
Supply Voltage LX Pin Voltage Output Voltage EXT Pin Voltage VOUT Pin Voltage VDOUT Pin Voltage CE Pin Voltage Input Voltage VDIN Pin Voltage A Version B Version
– 0.3 to +12 Vss–0.3 to +12 Vss–0.3 to VDD +0.3 Vss–0.3 to VDD +0.3 Vss–0.3 to +12 Vss–0.3 to VDD +0.3 Vss–0.3 to VDD +0.3 Vss– 0.3 to +12 250 50 300 –30 to +80 –55 to +125 260˚C, 10s
V V V V V V V mA mA mW ˚C ˚C
VDIN ILX IEXT PD Topt Tstg Tsolder Power Dissipation
Inductor Drive Output Current
Lx Pin Current EXT Pin Current
Operating Temperature Range Storage Temperature Range Lead Temperature (Soldering)
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum ratings are threshold limit values that must not be exceeded even for an instant under any conditions. Moreover, such values for any two items must not be reached simultaneously. Operation above these absolute maximum ratings may cause degradation or permanent damage to the device. These are stress ratings only and do not necessarily imply functional operation below these limits.
4
RS5RM
ELECTRICAL CHARACTERISTICS
• RS5RM3624A,B Symbol Item Conditions MIN. TYP. MAX. Unit
Topt=25˚C
Note
VIN VDD Voscst Vhold fosc Maxdty VOL1 IOH1 VLXlim VOH VOL2 VOUT VDIF
Operation Input Voltage Step-up Output Voltage Oscillator Start-up Voltage Hold-on Voltage Oscillator Frequency Oscillator Maximum Duty Cycle Lx Output Voltage Lx Leakage Current Lx Voltage Limit EXT Output Pch ON Voltage EXT Output Nch ON Voltage Output Voltage Dropout Voltage
No load No load No load IOUT=1mA
1.2 3.99 4.1 0.9 0.7 40 65 50 80
10 4.21 1.2
V V V V
60 90 0.5
kHz % V µA V V
IOL=50mA 0.01 LX Pin On IEXT=–3mA,VDD=4.1V IEXT=5mA,VDD=4.1V IRL=–5mA IRL=–30mA –30mA≤IRL≤0mA 2.34 60 IOL=5mA 0.01 VDIN=VDD VDIN=Vss –0.5 VDD – 0.3 0 CE=VDD CE=Vss VIN=3V, L=100µH, –0.5 –0.5 2.4 120 3.51 3.6 0.3 3.6 0.9
10
0.5 3.69
V V V
∆VOUT/∆IOUT Load Regulation –VDET VHYS VOL3 IOH2 IVDINH IVDINL VCEH VCEL ICEH ICEL IDD Detector Threshold Detector Threshold Hysteresis VDOUT ON Voltage VDOUT Leakage Current VDIN “H” Input Current VDIN “L” Input Current CE “H” Input Voltage CE “L” Input Voltage CE “H” Input Current CE “L” Input Current Supply Current
100 2.46 240 0.5 5 5 0.5 VDD 0.2VDD 0.5 0.5
mV V mV V µA µA µA V V µA µA
C=22µF, CE=Vss, No load VIN=3V, L=100µH,
55
120
µA
1.0 10.0
µA µA
Note1 Note2
Istandby
Standby Current
C=22µF, CE=VDD, No load
(Note 1) Standby current of Version A (Note 2) Standby current of Version B Please refer to Basic Circuit for Test Circuit.
5
RS5RM
• RS5RM5045A,B Symbol Item Conditions MIN. TYP. MAX. Unit
Topt=25˚C
Note
VIN VDD Voscst Vhold fosc Maxdty VOL1 IOH1 VLXlim VOH VOL2 VOUT VDIF
Operation Input Voltage Step-up Output Voltage Oscillator Start-up Voltage Hold-on Voltage Oscillator Frequency Oscillator Maximum Duty Cycle Lx Output Voltage Lx Leakage Current Lx Voltage Limit EXT Output Pch ON Voltage EXT Output Nch ON Voltage Output Voltage Dropout Voltage
No load No load No load IOUT=1mA
1.2 5.36 5.5 0.9 0.7 40 65 50 80
10 5.64 1.2
V V V V
60 90 0.5
kHz % V µA V V
IOL=50mA 0.01 LX Pin On IEXT=–3mA,VDD=5.5V IEXT=5mA,VDD=5.5V IRL=–5mA IRL=–30mA –30mA≤IRL≤0mA 4.38 112 IOL=5mA 0.01 VDIN=VDD VDIN=Vss –0.5 VDD –0.3 0 CE=VDD CE=Vss VIN=4V, L=100µH, –0.5 –0.5 4.5 225 4.87 5.0 0.3 5.0 0.9
10
0.5 5.13
V V V
∆VOUT/∆IOUT Load Regulation –VDET VHYS VOL3 IOH2 IVDINH IVDINL VCEH VCEL ICEH ICEL IDD Detector Threshold Detector Threshold Hysteresis VDOUT ON Voltage VDOUT Leakage Current VDIN “H” Input Current VDIN “L” Input Current CE “H” Input Voltage CE “L” Input Voltage CE “H” Input Current CE “L” Input Current Supply Current
100 4.62 450 0.5 5 5 0.5 VDD 0.2VDD 0.5 0.5
mV V mV V µA µA µA V V µA µA
C=22µF, CE=Vss, No load VIN=4V, L=100µH,
70
150
µA
1.0 10.0
µA µA
Note1 Note2
Istandby
Standby Current
C=22µF, CE=VDD, No load
(Note 1) Standby current of Version A (Note 2) Standby current of Version B Please refer to Basic Circuit for Test Circuit.
6
RS5RM
OPERATION OF STEP-UP DC/DC CONVERTER
Step-up DC/DC Converter charges energy in the inductor when Lx Transistor (LxTr) is ON, and discharges the energy with the addition of the energy from Input Power Source thereto when LxTr is OFF, so that a higher output voltage than the input voltage is obtained. The operation will be explained with reference to the following diagrams :
< Basic Circuits > i2 L VIN i1 LX Tr CL SD IOUT VOUT IL
< Current through L >
IL min
IL max topen t
ton T=1/ fosc
toff
Step.1: LxTr is turned ON and current IL (=i1 ) flows, so that energy is charged in L. At this moment, IL(=i1 ) is increased from ILmin (=0) to reach ILmax in proportion to the on-time period (ton) of LxTr. Step.2: When LxTr is turned OFF, Schottky diode (SD) is turned ON in order that L maintains IL at ILmax, so that current IL (=i2) is released. Step.3: IL (=i2) is gradually decreased, and in the case of discontinuous mode, IL reaches ILmin (=0) after a time period of topen, so that SD is turned OFF. In the case of a continuous mode,the time period (toff) runs out before IL reaches ILmin (=0), so that LxTr is turned ON in the next cycle, and SD is turned OFF. In this case, ILmin does not reach zero, and IL (=i1) increases from ILmin (>0). In the case of PWM control system, with the oscillator frequency (fosc) maintained constant, the output voltage is maintained constant by controlling the on-time period (ton).
(Note) Please refer to the Application Manual for “RH5RH SERIES” for details.
7
RS5RM
OPERATION
VIN 100µH LX VDD
8
6 5 Pch Tr
VOUT
VOUT
OSC 100µF LX Tr PWM
– + + –
22µF Vref1 1 VSS Vref2
1µF
FIG. A Diagram of RS5RM including external circuits 1. VDD Output Voltage VDD output voltage is shown in Fig. B. (1) In the case of VIN –Vf ≥VDD0: In Area B, LxTr is maintained in an OFF state, so that VIN–Vf (V) is output as it is from VDD pin without step-up operation. (2) In the case of VIN–Vf
