TPS60120, TPS60121, TPS60122, TPS60123, TPS60124, TPS60125
REGULATED 200-mA HIGH EFFICIENCY CHARGE PUMP
DC/DC CONVERTERS
SLVS257B NOVEMBER 1999 REVISED AUGUST 2000
1
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
features
D
High Average Efficiency Over Input Voltage
Range Because of Special Switching
Topology
D
Minimum 200-mA Output Current From an
Input Voltage Range of 1.8-V to 3.6-V
D
Regulated 3.3-V or 3-V
4% Output Voltage
D
No Inductors Required, Low EMI
D
Only Four External Components Required
D
55-
A Quiescent Supply Current
D
0.05-
A Shutdown Current
D
Load Disconnected in Shutdown
D
Integrated Low Battery and Power Good
Detectors
D
Evaluation Module Available
(TPS60120EVM-142)
applications
D
Applications Powered by Two Battery Cells
D
Portable Instruments
D
Battery-Powered Microprocessor Systems
D
Miniature Equipment
D
Backup-Battery Boost Converters
D
PDAs, Organizers, Laptops
D
MP-3 Portable Audio Players
D
Handheld Instrumentation
D
Medical Instruments (e.g., Glucose Meters)
D
Cordless Phones
description
The TPS6012x step-up, regulated charge pumps
generate a 3.3-V or 3-V
4% output voltage from
a 1.8-V to 3.6-V input voltage (two alkaline, NiCd,
or NiMH batteries). They can deliver an output
current of at least 200 mA (100 mA for the
TPS60122 and TPS60123), all from a 2-V input.
Four external capacitors are needed to build a
complete high efficiency dc/dc charge pump
converter. To achieve the high efficiency over a
wide input voltage range, the charge pump
automatically selects between a 1.5x or doubler
conversion mode. From a 2-V input, all ICs can
start with full load current.
The devices feature the power-saving pulse-skip
mode to extend battery life at light loads.
TPS60120, TPS60122, and TPS60124 include a
low battery comparator. TPS60121, TPS60123,
and TPS60125 feature a power-good output. The
logic shutdown function reduces the supply
current to a maximum of 1
A and disconnects the
load from the input. Special current-control
circuitry prevents excessive current from being
drawn from the battery during start-up. This dc/dc
converter requires no inductors, therefore EMI is
of low concern. It is available in the small,
thermally enhanced 20-pin PowerPAD
t
package
(PWP).
IO = 66 mA
0
10
20
30
40
50
60
70
80
90
100
1.8
2
2.2
2.4 2.6
2.8
3
3.2
3.4 3.6
VI Input Voltage V
Efficiency %
IO = 164 mA
IO = 216 mA
IO = 116 mA
VO = 3.3 V
TC = 25
C
IN
IN
LBI
C1+
C1
ENABLE
PGND GND
OUT
OUT
FB
LBO
C2+
C2
CO
22
F
Ci
10
F
Output
3.3 V
C2
2.2
F
C1
2.2
F
R1
R2
Input
1.8 V to 3.6 V
OFF/ON
efficiency (TPS60120, TPS60121)
typical operating circuit
R3
TPS60120
Copyright
2000, Texas Instruments Incorporated
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
PowerPAD is a trademark of Texas Instruments Incorporated.
TPS60120, TPS60121, TPS60122, TPS60123, TPS60124, TPS60125
REGULATED 200-mA HIGH EFFICIENCY CHARGE PUMP
DC/DC CONVERTERS
SLVS257B NOVEMBER 1999 REVISED AUGUST 2000
2
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
GND
GND
ENABLE
FB
OUT
C1+
IN
C1
PGND
PGND
GND
GND
LBI
LBO
OUT
C2+
IN
C2
PGND
PGND
PWP PACKAGE
(TPS60120, TPS60122, TPS60124)
(TOP VIEW)
Thermal Pad
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
GND
GND
ENABLE
FB
OUT
C1+
IN
C1
PGND
PGND
GND
GND
NC
PG
OUT
C2+
IN
C2
PGND
PGND
PWP PACKAGE
(TPS60121, TPS60123, TPS60125)
(TOP VIEW)
AVAILABLE OPTIONS
TA
PART NUMBER
PACKAGE
DEVICE FEATURES
TPS60120PWP
2 Cell to 3 3 V 200 mA
Low battery detector
TPS60121PWP
2-Cell to 3.3 V, 200 mA
Power good detector
40
C to 85
C
TPS60122PWP
PWP
20-Pin thermally
2 Cell to 3 3 V 100 mA
Low battery detector
40
C to 85
C
TPS60123PWP
PWP
y
enhanced TSSOP
2-Cell to 3.3 V, 100 mA
Power good detector
TPS60124PWP
2-Cell to 3 V 200 mA
Low battery detector
TPS60125PWP
2-Cell to 3 V, 200 mA
Power good detector
The PWP package is available taped and reeled. Add R suffix to device type (e.g. TPS60120PWPR) to order quantities of 2000
devices per reel.
TPS60120, TPS60121, TPS60122, TPS60123, TPS60124, TPS60125
REGULATED 200-mA HIGH EFFICIENCY CHARGE PUMP
DC/DC CONVERTERS
SLVS257B NOVEMBER 1999 REVISED AUGUST 2000
3
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
functional block diagram
_
+
Charge Pump
Power Stages
IN
C1+
C1
OUT
PGND
IN
C2+
C2
OUT
PGND
FB
Oscillator
Control
Circuit
_
+
+
VREF
_
+
+
Shutdown/
Start-Up
Control
0.8 VI
+
VREF
LBI
GND
LBO
ENABLE
C1F
C2F
TPS60120, TPS60122, TPS60124
_
+
Charge Pump
Power Stages
IN
C1+
C1
OUT
PGND
IN
C2+
C2
OUT
PGND
FB
Oscillator
Control
Circuit
_
+
+
VREF
_
+
+
Shutdown/
Start-Up Control
0.8 VI
+
VREF
GND
PG
ENABLE
C1F
C2F
TPS60121, TPS60123, TPS60125
TPS60120, TPS60121, TPS60122, TPS60123, TPS60124, TPS60125
REGULATED 200-mA HIGH EFFICIENCY CHARGE PUMP
DC/DC CONVERTERS
SLVS257B NOVEMBER 1999 REVISED AUGUST 2000
4
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
Terminal Functions
TERMINAL
I/O
DESCRIPTION
NAME
NO.
I/O
DESCRIPTION
C1+
6
Positive terminal of the flying capacitor C1
C1
8
Negative terminal of the flying capacitor C1
C2+
15
Positive terminal of the flying capacitor C2
C2
13
Negative terminal of the flying capacitor C2
ENABLE
3
I
ENABLE input. Connect ENABLE to IN for normal operation. When ENABLE is a logic low, the device turns off and
the supply current decreases to 0.05
A. The output is disconnected from the input when the device is placed in
shutdown.
FB
4
I
Feedback input. Connect FB to OUT as close to the load as possible to achieve best regulation. Resistive divider
is on the chip to match the internal reference voltage of 1.21 V.
GND
1, 2,
19, 20
Ground. Analog ground for internal reference and control circuitry. Connect to PGND through a short trace.
IN
7,14
I
Supply input. Connect to an input supply in the 1.8-V to 3.6-V range. Bypass IN to PGND with a (CO/2)
F capacitor.
Connect both INs through a short trace.
LBO/PG
17
O
Low battery detector output or power good output. Open drain output of the low battery or power-good comparator.
It can sink 1 mA. A 100-k
to 1-M
pullup is recommended. Leave terminal unconnected if not used.
LBI/NC
18
I
Low battery detector input (TPS60120/TPS60122/TPS60124 only). The input is compared to the internal 1.21-V
reference voltage. Connect terminal to ground if the low-battery detector function is not used. On the TPS60121,
TPS60123, and TPS60125, this terminal is not connected.
OUT
5, 16
O
Regulated power output. Connect both OUT terminals through a short trace and bypass OUT to GND with the output
filter capacitor CO.
PGND
912
Power ground. Charge-pump current flows through this pin. Connect all PGND pins together.
detailed description
operating principle
The TPS6012x charge pumps provide a regulated 3.3-V or 3-V output from a 1.8-V to 3.6-V input. They are
designed for a maximum load current of at least 200 mA or 100 mA, respectively. Designed specifically for
space-critical, battery-powered applications, the complete charge pump circuit requires only four external
capacitors. The circuit is optimized for efficiency over a wide input voltage range.
The TPS6012x charge pumps consist of an oscillator, a 1.21-V bandgap reference, an internal resistive
feedback circuit, an error amplifier, high current MOSFET switches, a shutdown/start-up circuit, a low-battery
or power-good comparator, and a control circuit (see the functional block diagram).
The device consists of two single-ended charge pumps. The power stages of the charge pump are automatically
configured to amplify the input voltage with a conversion factor of 1.5 or 2. The conversion ratio depends on
input voltage and output current. With input voltages lower than approximately 2.4 V, the convertor will run in
a voltage doubler mode with a gain of two. With a higher input voltage, the converter operates with a gain of
1.5. This assures high efficiency over the wide input voltage range of a two-cell battery stack and is further
described in the
adaptive mode switching section.
adaptive mode switching
The ON-resistance of the MOSFETs that are in the charge path of the flying capacitors is regulated when the
charge pump operates in voltage doubler-mode. It is changed depending on the output voltage that is fed back
into the control loop. This way, the time-constant during the charging phase can be modified and increased
versus a time-constant for fully switched-on MOSFETs. The ON-resistance of both switches and the
capacitance of the flying capacitor define the time constant. The MOSFET switches in the discharge path of the
charge pump are always fully switched on to their minimum r
DS(on)
. With the time-constant during charge phase
being larger than the time constant in discharge phase, the voltage on the flying capacitors stabilizes to the
lowest possible value necessary to get a stable V
O
.
TPS60120, TPS60121, TPS60122, TPS60123, TPS60124, TPS60125
REGULATED 200-mA HIGH EFFICIENCY CHARGE PUMP
DC/DC CONVERTERS
SLVS257B NOVEMBER 1999 REVISED AUGUST 2000
5
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
adaptive mode switching (continued)
The voltage on the flying capacitors is measured and compared with the supply voltage (V
I
). If the voltage across
the flying capacitors is smaller than half of the supply voltage, then the charge pump switches into the 1.5x
conversion-mode. The charge pump switches back from a 1.5x conversion-mode to a voltage doubler mode
if the load current in 1.5x conversion-mode can no longer be delivered.
With this control mode the device runs in doubler-mode at low V
I
and in 1.5x conversion-mode at high V
I
to
optimize the efficiency. The most desirable doubler mode is automatically selected depending on both V
I
and
I
L
. This means that at light loads the device selects the 1.5x conversion-mode already at smaller supply voltages
than at heavy loads.
The TPS6012x output voltage is regulated using the
ACTIVE-CYCLE regulation. An active cycle controlled
charge pump utilizes two methods to control the output voltage. At high load currents it varies the on resistances
of the internal switches and keeps the ratio ON/OFF time (=frequency) constant. That means the charge pump
runs at a fixed frequency. It also keeps the output voltage ripple as low as in linear-mode. At light loads the
internal resistance and also the amount of energy transferred per pulse is fixed and the charge pump regulates
the voltage by means of a variable ratio of ON-to-OFF time. In this operating point, it runs like a skip mode
controlled charge pump with a very high internal resistance, which also enables a low ripple in this operation
mode. Since the charge pump does effectively switch at lower frequencies at light loads, it achieves a low
quiescent current.
pulse-skip mode
In pulse-skip mode the error amplifier disables switching of the power stages when it detects an output higher
than the nominal output voltage. The oscillator halts and the IC then skips switching cycles until the output
voltage drops below the nominal output voltage. Then the error amplifier reactivates the oscillator and starts
switching the power stages again. The pulse-skip regulation mode minimizes operating current because it does
not switch continuously and deactivates all functions except bandgap reference, error amplifier, and
low-battery/power-good comparator when the output is higher than the nominal output voltage. When switching
is disabled from the error amplifier, the load is also isolated from the input. In pulse-skip mode, a special current
control circuitry limits the peak current. This assures moderate output voltage ripple and also prevents the
device from drawing excessive current spikes out of the battery.
start-up procedure
During start-up, i.e., when ENABLE is set from logic low to logic high, the output capacitor is charged up with
a limited current until the output voltage (V
O
) reaches 0.8
V
I
. When the start-up comparator detects this voltage
limit, the IC begins switching. This start-up charging of the output capacitor ensures a short start-up time and
eliminates the need of a Schottky diode between IN and OUT. The IC starts into a maximum load resistance
of V
O(nom)
/I
O(max)
.
shutdown
Driving ENABLE low places the device in shutdown mode. This disables all switches, the oscillator, and control
logic. The device typically draws 0.05
A (1
A max) of supply current in this mode. Leakage current drawn from
the output is as low as 1
A max. The device exits shutdown once ENABLE is set to a high level. The typical
no-load shutdown exit time is 10
s. When the device is in shutdown, the load is isolated from the input.
undervoltage lockout and short-circuit current limit
The TPS6012x devices have an undervoltage lockout feature that deactivates the device and places it in
shutdown mode when the input voltage falls below the typical threshold voltage of 1.6 V. During a short-circuit
condition at the output, the current is limited to 115 mA.
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