View HV857LMG-G_4124104.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

HV857L Low Noise, High Voltage EL Lamp Driver IC
Features
Audible noise reduction 190 VPP output voltage for higher brightness Single cell lithium ion compatible 150nA shutdown current Wide input voltage range 1.8V to 5.0V Separately adjustable lamp and converter frequencies Output voltage regulation Split supply capability Available in DFN-8 and MSOP-8 packages
General Description
The Supertex HV857L is a low noise, high voltage driver designed for driving Electroluminescent (EL) lamps of up to five square inches. It is the low noise version of the EL lamp driver HV857. The input supply voltage range is from 1.8V to 5.0V. The device uses a single inductor and a minimum number of passive components. The nominal regulated output voltage that is applied to the EL lamp is 95V. The chip can be enabled/disabled by connecting the resistor on RSW-Osc to VDD/ground. The HV857L has two internal oscillators, a switching MOSFET, and a high voltage EL lamp driver. The frequency for the switching MOSFET is set by an external resistor connected between the RSW-Osc pin and the supply pin, VDD. The EL lamp driver frequency is set by an external resistor connected between the REL-Osc and VDD pins. An external inductor is connected between the LX and VDD pins, or VIN for split supply applications. A 0.003-0.1F capacitor is connected between CS and ground. The EL lamp is connected between the VA and VB pins. The switching MOSFET charges the external inductor and discharges it into the capacitor at CS. The voltage at CS will start to increase. Once the voltage at CS reaches a nominal value of 95V, the switching MOSFET is turned OFF to conserve power. The outputs VA and VB are configured as an H bridge, and are switching in opposite states to achieve 95V across the EL lamp.
Applications
Mobile cellular phones Keypad backlighting LCD backlighting PDAs Handheld wireless communication products Global Positioning Systems (GPS)
Typical Application Circuit
ON = VDD OFF = 0 Enable Signal
+ VDD _ + VIN _
CDD
1 RSW 2 3
VDD RSW-Osc REL-Osc GND
VA VB CS LX
8 EL Lamp 7 6 D 5 CS LX
CIN
REL 4
HV857LMG
HV857L
Ordering Information
Device HV857L Package Options 8-Lead DFN (K7) HV857LK7-G 8-Lead MSOP (MG) HV857LMG-G
-G indicates package is RoHS compliant (`Green')
Absolute Maximum Ratings
Parameter Supply Voltage, VDD Operating Temperature Storage Temperature DFN-8 Power Dissipation MSOP-8 Power Dissipation Output voltage, VCS Value -0.5V to 6.5V -40C to +85C -65C to +150C 1.6W 300mW -0.5 to +120V
Pin Configuration
Top View
VDD 1 RSW-Osc 2 8 7 VA VB CS LX
MSOP-8
REL-Osc 3 GND 4 6 5
HV857LMG
VDD RSW-Osc REL-Osc 1 2 3 4 8 VA VB CS LX
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not implied. Continuous operation of the device at the absolute rating level may affect device reliability. All voltages are referenced to device ground.
DFN-8
7 6 5
Thermal Resistance
Package DFN-8 MSOP-8
Mounted on FR4 board, 25mm x 25mm x 1.57mm
ja 60OC/W 330 C/W
O
GND
HV857LK7
Pads are at the bottom of the package Exposed center pad is at ground potential
Recommended Operating Conditions
Symbol VDD fEL TA Parameter Supply voltage Operating drive frequency Operating temperature Min 1.8 -40 Typ Max 5.0 1 +85 Units V kHz
O
Conditions -------
C
Enable/Disable Function Table
Symbol EN-L EN-H Parameter Logic input low voltage Logic input high voltage Min 0 VDD - 0.2 Typ Max 0.2 VDD Units V V Conditions VDD = 1.8V to 5.0V VDD = 1.8V to 5.0V
Electrical Characteristics
DC Characteristics (Over recommended operating conditions unless otherwise specified, T
Symbol RDS(ON) VCS VA - VB IDDQ Parameter On-resistance of switching transistor Max. output regulation voltage Peak to Peak output voltage Quiescent VDD supply current Min 85 170 Typ 95 190 Max 6.0 105 210 150
A
= 25C)
Units V V nA
Conditions I = 100mA VDD = 1.8V to 5.0V VDD = 1.8V to 5.0V RSW-Osc = Low
2
HV857L
Electrical Characteristics (cont.)
Symbol IDD IIN VCS fEL fSW D Parameter Input current going into the VDD pin Input current including inductor current Output voltage on VCS EL lamp frequency Switching transistor frequency Switching transistor duty cycle Min 175 65 Typ 25 92 205 77 88 Max 150 40 235 89 Units A mA V Hz kHz % Conditions VDD = 1.8V to 5.0V. See Figure 1 See Figure 1* See Figure 1 See Figure 1 See Figure 1 See Figure 1
* The inductor used is a 220H Murata inductor, max DC resistance of 8.4, part # LQH32CN221K21.
Block Diagram
LX VDD CS
RSW-Osc
Switch Osc
Q
GND
+ Disable C _ VREF
VSENSE High Voltage Level Translators
Q
VA
VDD EL Osc
Q
REL-Osc
VB
Q
Figure 1: Typical Application/ Test Circuit
ON = VDD OFF = 0V 3.0in2 EL lamp
1 2 3
Enable Signal
+
VDD
560k 0.1F
VDD RSW-Osc REL-Osc
VA 8 VB 7 CS 6 BAS21 LX 5
-
2.0M
4 GND
+
VIN
HV857LMG
4.7F 220H* 3.3nF, 100V
* Murata Inductor LQH32CN221K21
3
HV857L
Typical Performance
Device HV857LMG-G Lamp Size 3.0in2 VDD = VIN 3.3V IIN 25.40mA VCS 92V fEL 205Hz Brightness 5.70ft-lm
Typical Performance Curves for Figure 1 (EL Lamp = 3.0in , V
2
DD
= 3.0V)
VCS vs VIN
105 85 75 65 55 1.5 2.5 3.5 4.5 5.5 33
IIN vs VIN IIN (mA)
28 23 18 13 1.5 2.5 3.5 4.5 5.5
VCS (V)
95
Vin (V) Brightness vs VIN
7 6 5 4 3 2 1 1.5 2.5 3.5 4.5 5.5
VIN (V)
IIN vs VCS
34
Brightness (ft-lm)
IIN (mA)
29 24 19 14 55 65 75 85 95 105
VIN (V)
VCS (V)
Typical Waveform on VA, VB and Differential Waveform VA - VB
4
HV857L
External Component Description
External Component Diode CS Capacitor Description Fast reverse recovery diode, BAS21 diode or equivalent. 0.003F to 0.1F, 100V capacitor to GND is used to store the energy transferred from the inductor. The EL lamp frequency is controlled via an external REL resistor connected between REL-Osc and VDD of the device. The lamp frequency increases as REL decreases. As the EL lamp frequency increases, the amount of current drawn from the battery will increase and the output voltage VCS will decrease. The color of the EL lamp is dependent upon its frequency. REL Resistor A 2M resistor would provide lamp frequency of 205Hz. Decreasing the REL resistor by a factor of 2 will increase the lamp frequency by a factor of 2. fEL = (2M)(205Hz) REL
RSW Resistor
The switching frequency of the converter is controlled via an external resistor, RSW, between RSW-Osc and VDD of the device. The switching frequency increases as RSW decreases. With a given inductor, as the switching frequency increases, the amount of current drawn from the battery will decrease and the output voltage, VCS, will also decrease. (560k)(77kHz) RSW
fSW =
LX Inductor
The inductor LX is used to boost the low input voltage by inductive flyback. When the internal switch is on, the inductor is being charged. When the internal switch is off, the charge stored in the inductor will be transferred to the high voltage capacitor CS. The energy stored in the capacitor is connected to the internal H-bridge, and therefore to the EL lamp. In general, smaller value inductors, which can handle more current, are more suitable to drive larger size lamps. As the inductor value decreases, the switching frequency of the inductor (controlled by RSW) should be increased to avoid saturation. A 220H Murata (LQH32CN221) inductor with 8.4 series DC resistance is typically recommended. For inductors with the same inductance value, but with lower series DC resistance, a lower RSW resistor value is needed to prevent high current draw and inductor saturation. As the EL lamp size increases, more current will be drawn from the battery to maintain high voltage across the EL lamp. The input power, (VIN x IIN), will also increase. If the input power is greater than the power dissipation of the package, an external resistor in series with one side of the lamp is recommended to help reduce the package power dissipation.
Lamp
Split Supply Configuration
The HV857L can also be used for handheld devices operating from a battery where a regulated voltage is available. This is shown in Figure 2. The regulated voltage can be used to run the internal logic of the HV857L. The amount of current necessary to run the internal logic is 150A maximum at a VDD of 5.0V. Therefore, the regulated voltage could easily provide the current without being loaded down.
Enable/Disable Configuration
The HV857L can be easily enabled and disabled via a logic control signal on the RSW and REL resistors as shown in Figure 2 below. The control signal, which can be from a microprocessor, has to track the VDD supply. RSW and REL are typically very high values. Therefore, only 10's of microamperes will be drawn from the logic signal when it is at a logic high (enable) state. When the microprocessor signal is high, the device is enabled, and when the signal is low, it is disabled.
5
HV857L
Figure 2: Split Supply and Enable/Disable Configuration
ON = VDD OFF = 0V Regulated Voltage = VDD CDD
1 VDD 2 RSW-Osc 3 REL-Osc
Enable Signal
RSW
VA 8 VB 7 EL Lamp CS 6 D LX 5 LX CS
REL
4 GND
Battery Voltage = VIN CIN
HV857LMG
Audible Noise Reduction
The EL lamp, when lit, emits an audible noise. This is due to EL lamp construction and it creates a major problem for applications where the EL lamp can be close to the ear such as cellular phones. The HV857L employs a circuit designed to help minimize the EL lamp's audible noise by slowing down the rise and fall times seen by the EL lamp.
6
HV857L
8-Lead DFN Package Outline (K7)
3x3mm body, 0.80mm height (max), 0.65mm pitch
D 8 D2 8
E Note 1 (Index Area D/2 x E/2)
E2
1
1
Note 1 (Index Area D/2 x E/2)
Top View
View B
Bottom View
Note 3
A
A3 b e
Seating Plane Note 2
L L1
A1
Side View
View B
Notes: 1. Details of Pin 1 identifier are optional, but must be located within the indicated area. The Pin 1 identifier may be either a mold, or an embedded metal or marked feature. 2. Depending on the method of manufacturing, a maximum of 0.15mm pullback (L1) may be present. 3. The inner tip of the lead may be either rounded or square.
Symbol MIN Dimension (mm) NOM MAX
A 0.70 0.75 0.80
A1 0.00 0.02 0.05
A3 0.20 REF
b 0.25 0.30 0.35
D 2.85 3.00 3.15
D2 1.60 2.50
E 2.85 3.00 3.15
E2 1.35 1.75
e 0.65 BSC
L 0.30 0.40 0.50
L1 0.15
0O 14O
JEDEC Registration MO-229, Variation WEEC-2, Issue C, Aug. 2003. Drawings not to scale
7
HV857L
8-Lead MSOP Package Outline (MG)
3x3mm body, 1.10mm height (max), 0.65mm pitch
D 8
1 (x4)
E E1
Note 1 (Index Area D1/2 x E1/2) L L2 Gauge Plane
1
L1
Seating Plane
Top View A
View B View B
A
A2
Seating Plane
A1
e
b
A
Side View
View A-A
Note 1: A Pin 1 identifier must be located in the index area indicated. The Pin 1 identifier may be either a mold, or an embedded metal or marked feature.
Symbol Dimension (mm) MIN NOM MAX
A 0.75 1.10
A1 0.00 0.15
A2 0.75 0.85 0.95
b 0.22 0.38
D 2.80 3.00 3.20
E 4.65 4.90 5.15
E1 2.80 3.00 3.20
e 0.65 BSC
L 0.40 0.60 0.80
L1 0.95 REF
L2 0.25 BSC
0 8
O
1 5O 15O
O
JEDEC Registration MO-187, Variation AA, Issue E, Dec. 2004. Drawings not to scale.
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to http://www.supertex.com/packaging.html.)
Doc.# DSFP-HV857L NR111306
8

▲Up To Search▲

Price & Availability of HV857LMG-G

	To Download HV857LMG-G Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .