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Positive/Negative Charge Pump for Voltage Bias General Description
The AAT3190 charge pump controller provides the regulated positive and negative voltage biases required by active matrix thin-film transistor (TFT) liquid-crystal displays (LCDs), CCD Sensors and OLEDs. Two low-power charge pumps convert input supply voltages ranging from 2.7-5.5V into two independent output voltages. The dual low-power charge pumps independently regulate a positive (VPOS) and a negative (VNEG) output voltage. These outputs use external diode and capacitor multiplier stages (as many stages as required) to regulate output voltages up to 25V. Built in soft start circuitry prevents excessive inrush current during start up. A high switching frequency enables the use of small external capacitors. The device's shutdown feature disconnects the load from VIN and reduces the quiescent current to less than 1.0 A. The AAT3190 is available in MSOP 8 or TSOPJW12 packages and is specified over a -40C to 85C operating temperature range
AAT3190
Features
* * * * * * * * * * * * *
ChargePumpTM
VIN Range: 2.7-5.5 Volts Adjustable dual charge pump Positive supply output up to +25V Negative supply output down to -25V Up to 30mA output current 1.0 MHz Switching Frequency < 1.0A Shutdown Current Internal power MOSFETs Internally controlled Soft-Start Fast Transient Response Ultra-Thin Solution (No Inductors) -40C to 85C Temperature Range Available in 8-Pin MSOP, 12-pin TSOPJW
Preliminary Information
Applications
* * * * * TFT Active-Matrix LCDs Passive-Matrix Displays Personal Digital Assistants (PDAs) CCD Sensor Voltage Bias Organic LEDs (OLED)
Typical Application
INPUT
IN
EN
EN
DRVN
AAT3190
DRVP FBN
NEGATIVE OUTPUT
REF FBP GND
POSTIVE OUTPUT
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Positive/Negative Charge Pump for Voltage Bias Pin Description
Pin #
MSOP-8 TSOPJW-12
AAT3190
Symbol
FBP
Function
Positive Charge-Pump Feedback Input. Regulates to 1.2V nominal. Connect feedback resistive divider to analog ground (GND). Enable Input. When EN is pulled low, the device shuts off and draws only 1.0A. When high, it is in normal operations. Drive EN through an external resistor. Internal Reference Bypass Terminal. Connect a 0.1 F capacitor from this terminal to analog ground (GND). External load capability to 50A. REF is disabled in shutdown. Negative Charge-Pump Regulator Feedback Input. Regulates to 0V nominal. Connect feedback resistive divider to the reference (REF). Positive Charge-Pump Driver Output. Output high level is VIN and low level is PGND. Ground Negative Charge-Pump Driver Output. Output high level is VIN, and low level is PGND. Input Voltage. 2.7 - 5.5 Volts.
1
5
2
4
EN
3
3
REF
4
2
FBN
5 6 7 8
12 8, 9, 10, 11 7 1
DVRP GND DRVN VIN
Pin Configuration
MSOP-8 (Top View) TSOPJW-12 (Top View)
FBP EN REF FBN
1
8
VIN DRVN GND DRVP
2
7
3
6
4
5
VIN FBN REF EN FBP N/C
1 2 3 4 5 6
12 11 10 9 8 7
DRVP GND GND GND GND DRVN
1 2
2
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Positive/Negative Charge Pump for Voltage Bias Absolute Maximum Ratings
Symbol
VIN VEN VN_CH VP_CH Other Inputs IMAX TJ TLEAD
1
AAT3190
Description
Input Voltage EN to GND DRVN to GND DRVP to GND REF, FBN, FBP to GND Continuous Current into DRVN, DRVP All Other Pins Operating Junction Temperature Range Maximum Soldering Temperature (at leads, 10 sec)
Value
-0.3 to 6 -0.3 to 6 -0.3V to (VIN + 0.3V) -0.3V to (VIN + 0.3V) -0.3V to (VIN + 0.3V) 200 10 -40 to 150 300
Units
V V V V V mA mA C C
Note 1: Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions specified is not implied. Only one Absolute Maximum rating should be applied at any one time.
Thermal Information
Symbol
JA JA PD PD
Description
Thermal Resistance (MSOP-8) Thermal Resistance (TSOPJW-12) 2 Maximum Power Dissipation (MSOP-8) (TA = 25C) 2, 3 Maximum Power Dissipation (TSOPJW-12) (TA = 25C)
2
Value
150 160 667 625
Units
C/W C/W mW mW
2, 4
Note 2: Mounted on a FR4 board. Note 3: Derate 6.7mW/C above 25C. Note 4: Derate 6.25mW/C above 25C.
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Positive/Negative Charge Pump for Voltage Bias Electrical Characteristics
(VIN= 5.0V, CREF = 0.1F, TA = -40 to 85C. Unless otherwise noted, typical values are at TA= 25C) Symbol
VIN UVLO IIN
AAT3190
Description
Input Supply Range Input Under Voltage Threshold Input Quiescent Supply Current
Conditions
VIN rising VIN Falling, 40 mV hysteresis (typ) VFBP = 1.5V, VFBN = -0.2V, no load on DRVN and DRVP VEN = 0 V
Min
2.7
Typ
1.8 1.6 400 0.1 1.0 0 1.5 1.0 20
Max
5.5
Units
V V
800 1.0 1.2 +100 +100 5.0 5.0
A A MHz mV nA k V nA k V V
ISD Shutdown Supply Current FOSC Operating Frequency Negative Low-Power Charge Pump VFBN FBN Regulation Voltage IFBN FBN Input Bias Current RDSNCHN DRVN NCH On-Resistance RDSPCHMIN MIN DRVN PCH On-Resistance RDSPCHMAX MAX DRVN PCH On-Resistance Positive Low-Power Charge Pump VFBP FBP Regulation Voltage IFBP FBP Input Bias Current RDSPCHP DRVP PCH On-Resistance RDSNCHMIN MIN DRVP NCH On-Resistance RDSNCHMIN MAX DRVP NCH On-Resistance Reference Reference Voltage VREF Reference Under Voltage Threshold Logic Signals VIL Input Low Voltage VIH Input High Voltage IIL Enable Input Low Current IIH Enable Input High Current Thermal Limit TSD Over Temp Shutdown Threshold THYST Over Temp Shutdown Hysteresis
0.8 -100 -100
VFBN = -50mV VFBN = 100mV, VIN = 4V VFBN = -100mV, VIN = 4V
VFBP = 1.5V VFBP = 1.15V, VIN = 4V VFBP = 1.25V, VIN = 4V -2.0 A < IREF < 50 A VREF rising
1.15 -60
1.2 1.0 3 20
1.25 +100 5.0 15
1.18
1.2 0.8
1.22
0.5 1.5 VIN = 5.0V, FBP = 1.5V, FBN = -0.2V VIN = 5.0V, FBP = 1.5V, FBN = -0.2V 140 15 1 1
V V A A C C
4
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Positive/Negative Charge Pump for Voltage Bias Typical Characteristics
Quiescent Current vs. Temperature
350 1000
AAT3190
Switching Frequency vs. Temperature
Quiescent Current (A)
Frequency (kHz)
10 35 60 85
330 310 290 270 250 -40
VFBP = 1.5V VFBN = -0.2V
950
900
850
800 -15 -40 -15 10 35 60 85
Temperature (C)
Temperature (C)
Reference Voltage vs. Temperature
1.22 15 12.5 10 7.5 5 2.5 0 -2.5 -5 -7.5 -10 -12.5 -15 2.5
Maximum VOUT vs. VIN IOUT = 5mA and 15mA
IOP = 5mA IOP = 15mA ION = 15mA ION = 5mA
3 3.5 4 4.5 5 5.5
Reference Voltage (V)
1.21
1.2
1.19
1.18 -40
-15
10
35
60
85
VOUT (V)
Temperature (C)
VIN (V)
Positive Output Voltage vs. Load Current TA = 25C
12.4
Negative Output Voltage vs. Load Current TA = 25C
-6.5
VIN = 5.0V
12.2 -6.75 -7 -7.25 -7.5 11.6 11.4 0 5 10 15 20 25 30 35 40 -7.75 -8 0
VIN = 5.0V
VPOS (V)
12 11.8
VNEG (V)
10
20
30
40
IPOS (mA)
INEG (mA)
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Positive/Negative Charge Pump for Voltage Bias Typical Characteristics
Positive Output Efficiency vs. Load Current VIN = 5.0V
80 70
AAT3190
Negative Output Efficiency vs. Load Current VIN = 5.0V
80 70
VPOS = 12.3V 85C
25C Efficiency (%)
85C 25C
Efficiency (%)
60 50 40 30 20 0 10 20 30 40
60 50 40 30 20 0 10 20 30 40
VNEG = -7.3V
IPOS (mA)
INEG (mA)
VPOS Load Transient
250 200 20 10 0 -10 -20 -30 -40 -50 -60 250 200
VNEG Load Transient
20 10 0 -10 -20 -30 -40 -50 -60
150 100 50 0 -50 -100 -150
VNEG (bottom trace) (50mV/div)
VPOS (bottom trace) (50mV/div)
150 100 50 0 -50 -100 -150
IPOS (top trace) (10mA/div)
INEG (top trace) (10mA/div)
50s/div
50s/div
AAT 3190 Power-Up Sequence
20 16
AAT3190-1 Power-Up Sequence
4 2 20 16 4
Enable
Enable
2 0
VPOS and VNEG (bottom traces, V)
VPOS and VNEG (bottom traces, V)
12 8 4 0 -4 -8 -12
0
12 8 4 0 -4 -8 -12
Enable (top trace, V)
Enable (top trace, V)
VPOS VNEG
-2 -4 -6 -8 -10 -12
VPOS
-2 -4 -6
VNEG
-8 -10 -12
500sec/div
500sec/div
6
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Positive/Negative Charge Pump for Voltage Bias Typical Characteristics
Output Ripple
VPOS = 12.3V, IPOS = 5mA, VNEG = 7.2V, INEG = 10mA
AAT3190
Positive Output Voltage vs. Load Current T = 85C
12.4
VIN = 5.0V VPOS (10mV/div) VPOS (V) VNEG (10mV/div) 500nsec/div
12.2 12 11.8 11.6 11.4
0 10 20 30 40
IPOS (mA)
Negative Output Voltage vs. Load Current T = 85C
-6.5 -6.75 -7
AAT3190 Reference Undervoltage Threshold
(120F capacitor placed across REF to limit rate of rise of REF for test purposes only) SHDN (2V/div) REF (0.2V/div) DRVN (2V/div)
VIN = 5.0V
VNEG (V)
-7.25 -7.5 -7.75 -8 0 10 20 30 40
0.5V
INEG (mA)
500nsec/div
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Positive/Negative Charge Pump for Voltage Bias Functional Block Diagram
AAT3190
IN
DRVP
UVLO
EN
Control
DRVN
Reference Oscillator
+ -
FBP
Over Temperature Protection
Band Gap Ref.
REF
GND
+
FBN
Functional Description
Dual Charge-Pump Regulators
The AAT3190 provides low power regulated output voltages from two individual charge pumps. Using a single stage, the first charge pump inverts the supply voltage (VIN) and provides a regulated negative output voltage. The second charge pump doubles VIN and provides a regulated positive output voltage. These outputs use external Schottky diodes and capacitor multiplier stages (as many as required) to regulate up to 25V. A constant switching frequency of 1MHz minimizes the output ripple and capacitor size.
Negative Charge Pump
During the first half-cycle, the P-channel MOSFET turns on, and the flying capacitor C7 charges to VIN minus a diode drop (figure 1). During the second half-cycle, the P-channel MOSFET turns off, and the N-channel MOSFET turns on, level shifting C7. This connects C7 in parallel with the output reservoir capacitor C10. If the voltage across C10 minus a diode drop is less than the voltage across C7, current flows from C7 to C10 until the diode turns off.
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Positive/Negative Charge Pump for Voltage Bias
IN
AAT3190
OSC
CTL
DRVN
C7
1/2 A4
BAT54SDW
FBN
R1
VON = -(R1/R2) x VREF VON
R2 C10 VREF 1.2V GND
AAT3190
C2
Figure 1: Negative Charge Pump Block Diagram
Positive Charge Pump
During the first half-cycle, the N-channel MOSFET turns on and charges the flying capacitor C4 (Figure 2). During the second half-cycle, the N-channel MOSFET turns off and the P-channel MOSFET
turns on, level shifting C4 by the input voltage. This connects C4 in parallel with the reservoir capacitor C5. If the voltage across C5 plus a diode drop is less that the level shifted flying capacitor (C4 + VIN), charge is transferred from C4 to C5 until the diode turns off.
IN
VIN OSC C4 CTL DRVP BAT54SDW 1/2 A3
FBP
R3
VOP VOP = (1+R3/R4) x VREF
VREF 1.2V
R4
C5
AAT3190
GND
Figure 2: Positive Charge Pump Block Diagram
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Positive/Negative Charge Pump for Voltage Bias
Voltage Reference
The voltage reference is a simple band gap with an output voltage equal to b VBE + K*VT. The band gap reference amplifier has an additional compensation capacitor from the negative input to the output. This capacitor serves to slow down the circuit during startup and soft starts the voltage reference, and the regulator output from overshoot. The reference circuit amplifier also increases the overall PSRR of the device. An 80 K resistor serves to isolate and buffer the amplifier from a small internal filter capacitor and an optional large external filter capacitor.
AAT3190
Design Procedure and Component Selection
Output Voltage
The number of charge pump stages required for a given output varies with the input voltage applied. The number of stages required can be estimated by VOP - VIN np = V - 2V IN F for the positive output and VON nn = 2V - V F IN for the negative output. When solving for np and nn round up the solution to the next highest integer to determine the number of stages required.
Enable and Start-up
The AAT3190 is disabled by pulling the EN pin low. The threshold levels lie between 0.5V and 1.5V. Even though the quiescent current of the IC during shutdown is less than 1A, the positive output voltage (VOP) and any load current associated with it does not disappear without the complete removal of the input voltage. This is due to the fact that with no switching of the DRVP pin, the input voltage simply forward biases the Schottky diodes associated with the VOP charge pump, providing a path for load current to be drawn from the input voltage. Depending on the application, the supplies must be sequenced properly to avoid damage or latch-up. The AAT3190 start-up sequence ramps up the VOP output 200sec after the VON output is present. The AAT3190-1 ramps up the positive supply before the negative supply.
VON
The negative output voltage is adjusted by a resistive divider from the output (VON) to the FBN and REF pin. The maximum reference voltage current is 50A therefore the minimum allowable value for R2 of figure 1 is 24k. It is best to select the smallest value possible for R2 as this will keep R1 to a minimum. This limits errors due to the FBN input bias current. The FBN input has a maximum input bias current of 100nA. Using the full 50A reference current for programming VON: VREF 1.2 IPGM = R2 = 24.1k = 50A will limit the error due to the input bias current at FBN to less than 0.2% IFBN 0.1A IPGM = 50A = 0.2%
Over Temperature Protection
A logic control circuit will shut down both charge pumps in the case of an over temperature condition.
UVLO (Under voltage lockout)
A UVLO circuit disables the AAT3190 when the input voltage supply is lower than 1.8V nominal.
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Positive/Negative Charge Pump for Voltage Bias
With R2 selected R1 can be determined. VNEG * R2 -VREF
AAT3190
Positive Output Capacitor Voltage Ratings
The absolute steady state maximum output voltage (neglecting the internal RDS(ON) drop of the internal MOSFETs) for the nth stage is VBULK(n) = (n + 1) * VIN - 2 * n * VFWD where VFWD is the estimated forward drop of the Schottky diode. This is also the voltage rating required for the nth bulk capacitor in the positive output charge pump. The voltage rating for the nth flying capacitor in the positive stage is VFLY(n) = VBULK(n + 1) - VFWD where VBULK(0) is the input voltage. VIN = 5.0V, VFWD = 0.3V Stages (n) VBULK(n)
1 2 3 4 5 6 9.4V 13.8V 18.2V 22.6V 27.0V 31.4V
R1 =
VOP
The positive output voltage is set by way of a resistive divider from the output (VOP) to the FBP and ground pin. Limiting the size of R4 reduces the effect of the FBP bias current. For less than 0.1% error limit R4 to less than 12 k. VREF 1.2V IPGM = R4 = 12k = 100A IFBP 0.1A IPGM = 100A = 0.1% Once R4 has been determined solve for R3. VO R3 = R4 * -1 VREF
VFLY(n)
4.7V 9.1V 13.5V 17.9V 22.3V 26.7V
Flying and Output Capacitor
The fly capacitor minimum value is limited by the output power requirement while the maximum value is set by the bandwidth of the power supply. If CFLY is too small the output may not be able to deliver the power demanded, while too large of a capacitor may limit the bandwidth and time required to recover from load and line transients. A 0.1F X7R or X5R ceramic capacitor is typically used. The voltage rating of the fly and reservoir output capacitors vary with the number of charge pump stages. The reservoir output capacitor should be roughly 10 times the fly capacitor. Use larger capacitors for reduced output ripple. A 1F X7R or X5R type ceramic is typically used.
Table 1. Positive Output Capacitor Voltages
Negative Output Capacitor Voltage Ratings
The absolute steady state maximum output voltage (neglecting the internal RDS(ON) drop of the internal MOSFETs) for the nth stage is VBULK(n) = -n * VIN + 2 * n * VFWD This is also the voltage rating required for the nth bulk capacitor in the negative output charge pump.
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Positive/Negative Charge Pump for Voltage Bias
The voltage rating for the nth flying capacitor in the negative stage is VFLY(n) = VFWD - VBULK(n)
AAT3190
Input Capacitors
Input Capacitor
The primary function of the input capacitor is to provide a low impedance loop for the edges of pulsed current drawn by the IC. A low ESL X7R or X5R type ceramic capacitor is ideal for this function. The size required will vary depending on the load, output voltage, and input voltage characteristics. Typically the input capacitor should be 5 to 10 times the fly capacitor. If the source impedance of the input supply is high, a larger capacitor may be required. To minimize stray inductance the capacitor should be placed as close as possible to the IC. This keeps the high frequency content of the input current localized, minimizing radiated and conducted EMI.
VIN = 5.0V, VFWD = 0.3V Stages (n) VBULK(n)
1 2 3 4 5 6 -4.4V -8.8V -13.2V -17.6V -22.0V -26.4V
VFLY(n)
4.7V 9.1V 13.5V 17.9V 22.3V 26.7V
Table 2. Negative Output Capacitor Voltages
Rectifier Diodes
For the rectifiers use Schottky diodes with a voltage rating of 1.5 times the input voltage. The maximum steady state voltage seen by the rectifier diodes for both the positive and negative charge pumps (regardless of the number of stages) is VREVERSE = VIN - VF The BAT54S dual Schottky is offered in a SOT23 package that provides a convenient pin-out for the voltage doubler configuration. The BAT54SDW quad Schottky in SOT363 (2x2mm) is a good choice for multiple-stage charge pump configuration (see evaluation board schematic).
Single Output Operation
If only one of the two channels is needed, it is possible to disable either output. Connect the respective FB pin to VIN to disable the output, e.g. connect FBN to VIN in order to disable the negative output.
PC Board Layout
The input and reference capacitor should be placed as close to the IC as possible. Place the programming resistors (R1-R4) close to the IC, minimizing trace length to FBN and FBP. Figure 3 and 4 display the evaluation board layout with the TSOPJW-12 package.
12
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Positive/Negative Charge Pump for Voltage Bias
AAT3190
Figure 3: AAT3190 Evaluation Board Top Side
Figure 4. AAT3190 Evaluation Board Bottom Side
VIN A4 BAT54SDW C9 0.1F C21 1F C10 0.1F R2 24.1k VON C2 C22 1F R1 139k 0.1F R4 6.02k AAT3190ITP GND C19, C20, C21, C22 Murata GRM39X5R105K16 1F 16V X5R 0603 C7, C8, C9, C10 Taiyo Yuden EMK107BJ104MA 0.1F 16V X7R 0603 C1 Taiyo Yuden JMK212BJ475MG 4.7F 6.3V X5R 0805 R3 56.2k A3 BAT54SDW C8 0.1F R5 205K
U1
1 2 3 4 5 6
VIN DRVP FBN REF EN FBP GND GND GND GND
12 11 10 9 8 7
C7 0.1F
C20 1F VOP
C1 4.7F
C19 1F
N/C DRVN
GND EN
Figure 5: AAT3190 Evaluation Board Schematic (shown with 2 stages) VOP = 12V, VON = -7V
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Positive/Negative Charge Pump for Voltage Bias Ordering Information
Package MSOP-8 TSOPJW-12 TSOPJW-12
Note 1: XYY = assembly and date code.
AAT3190
Power-Up Sequence -, + -, + +, -
Marking1 JDXYY JDXYY LKXYY
Part Number (Tape and Reel) AAT3190IKS-T1 AAT3190ITP-T1 AAT3190ITP-1-T1
Package Information
MSOP-8
4 4 1.95 BSC
3.00 0.10
4.90 0.10
0.60 0.20 PIN 1 0.254 BSC 0.95 REF
3.00 0.10 10 5 0.95 0.15 0.85 0.10
0.075 0.075 0.65 BSC 0.30 0.08
All dimensions in millimeters.
14
GAUGE PLANE
0.155 0.075
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Positive/Negative Charge Pump for Voltage Bias
TSOPJW-12
0.10 0.20 + 0.05 -
AAT3190
2.40 0.10
0.50 BSC 0.50 BSC 0.50 BSC 0.50 BSC 0.50 BSC
2.85 0.20
7 NOM 3.00 0.10
0.9625 0.0375 + 0.10 1.00 - 0.065
0.04 REF
0.055 0.045
4 4
0.010
0.15 0.05
0.45 0.15 2.75 0.25
All dimensions in millimeters.
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Positive/Negative Charge Pump for Voltage Bias
AAT3190
AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. AnalogicTech warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with AnalogicTech's standard warranty. Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed.
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830 E. Arques Avenue, Sunnyvale, CA 94085 Phone (408) 737-4600 Fax (408) 737-4611 16
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