ZD1680/ZD1680A High Efficiency Step-Up Controller for LEDs with 6 Channel Constant Current Driver.
Zywyn
Features
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Drives 6 Strings of Up to 16, Serially Connected LEDs
6 Channels of Current Sink at
50mA
Each Channel
Supports up to 15W with an External RSENSE Resistor
Greater Than 90% Efficiency
Adjustable LED Brightness with PWM or DC Voltage
through the ISET Pin
LED Currents Set By One External RSET Resistor
CHIP ENABLE (CE) Pin for Enable or Shutdown
VBST Pin to set a Higher Gate Drive Voltage (>VDD) for
More Efficient and Versatile N-Channel Power FETs can
be used
ALERT Output Signal for a Open/Short LED Indication
(ZD1680A only)
Output Over-Voltage Protection (OVP) Limiting, Exter-
nally Adjustable
Under Voltage Lockout, UVLO
Internal Soft Start Inrush Current Limiting
Internal Thermal Protection
Simpler, Low Cost, More Reliable Compared to CCFL
or EL Backlighting
Available in a 5x5mm 32-pin VQFN or a 28-pin Ex-
posed-TSSOP Green Package
Preliminary Information
ZD1680/ZD1680A
High Efficiency Step-Up Controller for LEDs with 6 Channel
Current Sink, Auxiliary Gate Drive and LED Open-Short Detection
General Description
The ZD1680/ZD1680A is a high efficiency step-up controller especially
designed for driving multiple strings of serially connected LEDs. 6 channels
of low dropout current sinks are included to provide excellent matching of
currents for each LED string. The boost converter control loop regulates
the current source outputs to 0.3V for maximum efficiency. All 6 channel
LED current outputs are set by a resistor RSET to ground at the ISET
pin. A CHIP ENABLE (CE) input provides an enable or shutdown function
to the IC and the ISET pin can be used to adjust the LED string current
with a PWM signal or a DC voltage. Each LED channel can be individu-
ally enabled for maximum flexibility. Unused channels must be disabled
for proper circuit operation. Also included is an Under Voltage Lockout
(UVLO) circuit to discontinue operation when input VDD falls below 2.7V
and automatic soft start to limit inrush currents during power start-up or
following a re-CHIP ENABLE function. An ALERT function (available for
ZD1680A only) at the SEL pin whenever two LEDs are either in a shorted
or open condition due to LED at fault or malfunction. Output Over-Voltage
Protection (OVP) is available by user-defined resistor network setting to
protect the LEDs and the IC.
The ZD1680/ZD1680A is available in a 5x5mm 32-pin VQFN or 28-pin
Exposed- TSSOP Green Package.
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Ordering Information
Part Number
ZD1680LEQ/
ZD1680ALEQ
ZD1680LEY/
ZD1680ALEY
ZD1680YEVB
Temperature Range
–40°C to +85°C
–40°C to +85°C
n/a
Package Type
32-Pin 5x5 VQFN
28-EP-TSSOP
Evaluation Board
for ZD1680LEY/
ZD1680ALEY
Evaluation Board
for ZD1680LEQ/
ZD1680ALEQ
Applications
• Battery-Powered Backlighting Applications
• LCD Panel And Monitor Display Backlighting And Plane-
lighting
• Navigation Panel Display Backlighting
• PMPs And Portable Handy Terminals
• Portable LED Projectors
• Street Lamps; Industrial Lighting
ZD1680QEVB
n/a
Please contact the factory for pricing and availability on T&R option.
Pin Configuration
GND
D2
GND
D5
D1
D3
D4
D6
32
SEL
ISET
EN1
EN2
EN3
EN4
EN5
EN6
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
31
30
29
28
27
26
25
24
23
GND
CB
Typical Application
EN3 1
EN4 2
EN5 3
EN6 4
CE 5
VDD 6
OVP 7
NC 8
NC 9
NC 10
NC 11
CSS 12
CS 13
PGND 14
ZD1680/
ZD1680A
22 VBST
21
20
19
18
17
NDRV
PGND
CS
CSS
NC
ZD1680/
ZD1680A
28 EN2
27 EN1
26 ISET
25 SEL
24 D1
23 D2
22 D3
21 D4
20 D5
19 D6
18 GND
17 CB
16 VBST
15 NDRV
+5V to +26.5V
VBAT T
C8
4.7μF
R5
330KΩ
L1
10μH
C4
1μF
VBST
C2
1μF
CB
VBST NDRV
CS
R2
100Ω
D1
VOUT
R4
10Ω
M1
W
L
C1
10μF
R6
4.7KΩ
OVP
PGND
+3V to +5.5V
C3
1nF
VDD
D1
RSENSE*
0.12Ω
10 ~ 16 LED's and
50mA max
per string
VDD
C6
1μF
EN1
EN1
EN2
EN2
ZD1680/
ZD1680A
D2
D3
EN3
EN3
D4
EN4
EN4
D5
EN5
EN5
EN6
CE
SEL
ISET
GND
OVP
VDD
NC
CE
NC
NC
NC
NC
D6
CSS
C10
100pF
(Optional)
EN6
CE
SEL
RSET
5KΩ
SEL = TEST Pin (ZD1680)
= ALERT Pin (ZD1680A)
5x5 32-VQFN
SEL = TEST Pin (ZD1680)
= ALERT Pin (ZD1680A)
28-Exposed-TSSOP
NOT E: ILED=250/RSET
*NOTE 1. External RSENSE to be used to increase inductor current for 11W output power.
Figure 1. ZD1680/ZD1680A high efficiency step-up control-
ler for LEDs with 6 channels of constant current sink and
Specifications subject to change without notice
enables
Zywyn
1
May 2008
Zywyn Corporation • Tel (408) 733-3225 • Fax (408) 733-3206 • Email sales@zywyn.com • www.zywyn.com
rev. 1.6
Zywyn Corporation
Absolute Maximum Ratings
These are stress ratings only and functional operation of the
device at these ratings or any other above those indicated
in the operation sections of the specifications is not implied.
Exposure to absolute maximum rating conditions for extended
periods of time may affect reliability.
Input Voltages (VDD) .................................... -0.3V to +6V
EN
1~6
, CE, ISET, ALERT, OVP ......... -0.3V to (VDD+0.3V)
VBST ....................................................................... +24V
V
D1~6
........................................................................ +6V
Extended Commercial
Operating Temperature Range ............... –40°C to +85°C
Maximum Junction Temperature, T
J
........................ +150°C
Storage Temperature Range .................... –65°C to +150°C
Lead Temperature (Soldering, 10 sec.) ..................... 300°C
Power Dissipation Per Package @ T
A
=+25°C
5x5 32-pin VQFN ......................................................... 2.5W
28-pin Exposed TSSOP ........................................... 3W
Thermal Resistance
Θ
JA
(28-EP-TSSOP) ................................................ 25°C/W
Θ
JC
(28-EP-TSSOP).................................................. 9°C/W
Θ
JA
(5x5 32-pin VQFN) ........................................... 34°C/W
Θ
JC
(5x5 32-pin VQFN) ............................................. 1°C/W
ZD1680/ZD1680A
Storage Considerations
Storage in a low humidity environment is preferred. Large high
density plastic packages are moisture sensitive and should
be stored in Dry Vapor Barrier Bags. Prior to usage, the parts
should remain bagged and stored below 40°C and 60%RH. If
the parts are removed from the bag, they should be used within
48 hours or stored in an environment at or below 20%RH.
If the above conditions cannot be followed, the parts should
be baked for four hours at 125°C in order remove moisture
prior to soldering. Zywyn ships product in Dry Vapor Barrier
Bags with a humidity indicator card and desiccant pack. The
humidity indicator should be below 30%RH
The information furnished by Zywyn has been carefully
reviewed for accuracy and reliability. Its application or use,
however, is solely the responsibility of the user. No responsibil-
ity of the use of this information become part of the terms and
conditions of any subsequent sales agreement with Zywyn.
Specifications are subject to change without the responsibility
for any infringement of patents or other rights of third parties
which may result from its use. No license or proprietary rights
are granted by implication or otherwise under any patent or
patent rights of Zywyn Corporation.
Specifications subject to change without notice
2
May 2008
rev. 1.6
Zywyn Corporation
Electrical Characteristics
T
A
= +25°C, VDD = +3.6V, VBATT=5V, VOUT=30V, unless otherwise noted.
Parameter
Operating Voltage (VDD)
Operating Supply Current
UVLO Threshold
UVLO Hysteresis
FB (D1~6) Regulation Voltage
CS Trip Voltage
Minimum OFF Time
Maximum ON Time
NDRV Driver Sink/Source Current
NDRV Driver RON
CE, EN
1~6
, V
IH
CE, EN
1~6
, V
IL
ILED Scale Factor K
ILED Output Current Sink (D1~6)
CE, EN
1~6
, ISET PWM Frequency
Maximum Power Output
VBST Range
ILED Current Accuracy
ILED Current Matching
Soft Start Time
ALERT Threshold Level
OVP Threshold Level
OVP Threshold Hysteresis
At OVP input pin
Trimmed, Average of D1~6 Channels
Un-trimmed
From supply start-up or chip re-enable (CE); No external capacitor at
CSS pin
Shorted LED condition (ZD1680A only)
With External RSENSE (NOTE 1c)
VDD
ILED=K/RSET
CE=VDD
10
VDD=5V, NDRV=2V
VDD=5V
1.4
Condition
(ZD1680)
Min
3.3
ZD1680/ZD1680A
Typ
260
2.7
150
300
300
1.0
15
0.4
4
Max
5.5
Units
V
μA
V
mV
mV
mV
μs
μS
A
Ω
V
0.4
250
50
10
15
13
3
5
250
2.5
0.5
35
V
mA
kHz
W
V
%
%
μs
V
V
mV
Note 1. a) VOUT ranges from 6V to 60V, depending on the # of LEDs in series and the type of N-MOSFET power device
used.
b) VBATT ranges: +5V ~ +12V; +12V ~ 18V; +18V ~ 26.5V.
c) Power Output depends on external RSENSE resistor to be used.
For RSENSE = 0.12Ω, POUT MAX = 11W
For RSENSE = 0.06Ω, POUT MAX = 15W
Note 2. See Table 1 for the suggested external components to be used for the VBATT ranges.
Table 1: Recommended external inductor values vs VBATT
VBATT Range
5V to 12V
12V to 18V
18V to 26.5V
Recommended value for L1 inductor
10μH
15μH
22μH
Comments
2 to 3 Li-Ion cells or car battery
4 Li-Ion cells battery
From CCFL power supply circuit or car
battery
Specifications subject to change without notice
3
May 2008
rev. 1.6
Zywyn Corporation
Block Diagram
ZD1680/ZD1680A
5V to 26.5V
VBATT
ZD1680/ZD1680A
L1 10μH
D1
Schottky
VOUT
C2
4.7μF
VBST may be connected to either VBAT or VDD
VBST
C3
1μF
CLK
OSCILLATOR
PFM
BOOST
CONVERTER
15V Clamp*
CB
W
L
LED's
Rsense
0.12Ω
fb_rst
6V Clamp*
PGND
COUT
4.7μF
NDRV
3V to 5.5V
VDD
C2
1μF
GND
VREF
VREF
CS
IN1
IN2
IN3
Q
6 CHANNEL
ERROR AMP
CSS
CSS
100pF
(Note: CSS is optional)
D1
EN1_EN6
CE
6
ENABLE LOGIC
6 CHANNEL
LOW DROP OUT
CURRENT SOURCES
D2
D3
D4
D5
D6
VOUT
R5
OVP
R6
OVP Comparator
ISET
(0.5V)
W
L
6 CHANNEL
ALERT SENSE
ISET
SEL
RSET
SEL = TEST Pin (ZD1680)
= ALERT Pin (ZD1680A)
* Clamping diodes available on ZD1680A only
Figure 2. ZD1680/ZD1680A typical block diagram with 6 channel current sinks, 6 channel enables/shutdown,
LED open/short ALERT status and Over-Voltage Protection (OVP)
Specifications subject to change without notice
4
May 2008
rev. 1.6
Zywyn Corporation
Pin Description
Pin Number
32-VQFN 28-TSSOP
1
25
Pin Name
TEST
ALERT
ISET
EN1
EN2
EN3
EN4
EN5
EN6
NC
5
6
7
8
9
10
11
12
CE
VDD
OVP
NC
NC
NC
NC
NC
CSS
Pin Function
ZD1680/ZD1680A
SEL = TEST Pin, for ZD1680 only
SEL = ALERT Pin, for ZD1680A only. Logic Output "HIGH" Indicates an Open/
Short LED in any of the 6 Strings.
Sets LED Current. Connects external resistor here. (ILED=250/RSET)
LED Channel 1 Enable.
LED Channel 2 Enable.
LED Channel 3 Enable.
LED Channel 4 Enable.
LED Channel 5 Enable.
LED Channel 6 ENable.
No Connect Pin. Do not use this pin for making connections.
Chip Enable Pin. Set HIGH to enable the chip.
Input Supply Voltage. Decouple with a 1μF capacitor min. 5.5V max internally
clamped (for ZD1680A only).
Output Over-Voltage Protection Input. Set OVP level with external R3//R4
resistor divider. (VOVP = [(R5+R6)/R6] x (0.5) )
No Connect Pin. Do not use this pin for making connections.
No Connect Pin. Do not use this pin for making connections.
No Connect Pin. Do not use this pin for making connections.
No Connect Pin. Do not use this pin for making connections.
No Connect Pin. Do not use this pin for making connections.
Place a capacitor here to increase the Soft Start time delay. Optional.
Typical cap value is 100 pF.
Note: Additional Soft Start time also increases the load and line step recovery
time.
Power FET Current-Sense Input. Connects a 0.12Ω, 1W resistor here to
PGND for 11W power output capability. (See Note 1c)
Power Ground.
Gate Driver Output for external N-channel power MOSFET.
Auxiliary Gate Drive Voltage. Connects to VBATT or VDD. Decouple with a
1μF capacitor to GND if supplied separately from VDD or VBATT. See
application notes for reference connections.
15V max and internally clamped. (for ZD1680A only)
High side logic decoupling capacitor, place a 1μF ceramic capacitor to VBST.
Ground.
Ground.
LED Current Sink #6.
LED Current Sink #5.
LED Current Sink #4.
LED Current Sink #3.
LED Current Sink #2.
LED Current Sink #1.
Ground.
2
3
4
5
6
7
8
9
10
11
12
13
14
15
.
16
17
18
26
27
28
1
2
3
4
19
20
21
22
13
14
15
16
CS
PGND
NDRV
VBST
23
24
25
26
27
28
29
30
31
32
17
18
19
20
21
22
23
24
CB
GND
GND
D6
D5
D4
D3
D2
D1
GND
Specifications subject to change without notice
5
May 2008
rev. 1.6
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