THV6520_Rev.1.00_E THV6520 Boost converter / Charge pump Description Features THV6520 is a controller IC power supply system with boost converter and charge pump circuit. The charge pump provide regulated TFT LCD gate-on and gate-off supplies. The chip includes a VCOM buffer and a gate slop circuit and LDO. Soft start / Over current protection / Under voltage lock out protection / Thermal shut down are built in. Mounted area is reducible by 24-pin QFN. ・Input voltage range : 2.5V – 5.5V ・Boost converter Maximum output voltage : 16V Switching limit current : 2A Feedback voltage accuracy : +/-1% Switching frequency : 640kHz / 1.2MHz ・Charge pump Feedback voltage accuracy : +/-2% Switching frequency : 320kHz / 600kHz ・LDO Feedback voltage accuracy : +/-1.3% Output short-circuit current : 350mA ・Buffer amplifier Output short-circuit current : +/-90mA ・Gate slop ・Detector ・Protection circuit Soft start Over current protection Under voltage lock out protection Thermal shut down ・4mm x 4mm QFN 24pin package Application ･Mobile phone display ・Car Navigator display ･Laptop/Netbook/Tablet PC display OSC FB PC AMP_NON AMP_OUT Block Diagram PGND Pin Configuration 24 23 22 21 20 19 VLS VIN FB LX PC VCC SS LX 1 18 AVDD VCC 2 17 VGH_OUT Boost VIN 3 VGH DOUT 4 LDO_FB 5 VGH_OUT 15 V_VGH VGH_FB VCC DC (Top view) 1/2OSC Detector 16 VGH_FB Exposed Thermal Pad AGND AVDD UVLO DIN SS V_VGH GDELAY 25 GNDEXP Gate slope GIN 14 GOUT OSC 13 RE 6 GR VLS 1/2OSC AVDD V_LDO LDO AMP_NON LDO 12 AMP_OUT LDO_FB GIN 11 GDELAY 10 DC 9 DOUT 8 DIN V_LDO 7 VGHM GOUT OSC OSC VIN LDO PGND OSC VCOM AGND Copyright© 2013 THine Electronics, Inc. All rights reserved. 1/12 THine Electronics, Inc. THV6520_Rev.1.00_E Absolute Maximum Ratings Parameter Symbol VCC VH1 VH2 VL Pd Tj Tstg VCC voltage AVDD, LX voltage V_VGH voltage DOUT, DIN, VDIN, V_LDO voltage Power dissipation Junction temperature (*1) Storage temperature range Rating 6.5 22 38 6.5 1.8 125 -55 to +150 Units V V V V W ℃ ℃ *1. The operating temperature range should perform a thermal design, after consulting the thermal characteristic. Please use it in the range which does not exceed junction temperature. Recommended Operating Conditions Parameter Min 2.5 6 VCC、V_LDO voltage AVDD voltage Typ - Max 5.5 15 Units V V 2.5 2.0 1.5 1.0 0 0.5 Power Dissipation [W] 3.0 3.5 Power Dissipation -40 -20 0 20 40 60 80 100 120 140 160 Operating Temperature [℃] Copyright© 2013 THine Electronics, Inc. All rights reserved. 2/12 THine Electronics, Inc. THV6520_Rev.1.00_E Pin Description Number Name 1 LX 2 VCC Function Boost converter switching output pin Supply voltage pin 3 SS Soft start set pin 4 5 6 7 8 9 AGND LDO_FB LDO V_LDO DIN DOUT Analog ground pin LDO feedback input pin LDO output pin LDO supply voltage pin Detector input pin Detector output pin 10 DC 11 GDELAY 12 GIN Gate slop start delay input pin Gate slop input pin 13 RE Gate slop set pin 14 GOUT 15 V_VGH 16 VGH_FB 17 VGH_OUT 18 AVDD 19 AMP_OUT 20 AMP_NON Gate slop output pin Supply voltage for gate slop pin Positive charge pump feedback sense input pin Positive charge pump output pin Charge pump supply and operational amplifier supply pin Buffer amplifier output pin Buffer amplifier non-inverting input pin Detector delay input pin Boost converter error amplifier output pin 21 PC 22 FB 23 24 OSC PGND Boost converter feedback voltage sense input pin Oscillator set pin Power ground pins 25 GND EXP Back side. Description This pin is switching output of boost converter. Power supply pin This pin is set by soft start for boost converter. Please connect capacitor to GND for soft start time. Analog ground of PMIC This pin is input for LDO feedback. This pin is output for LDO. This pin is input supply for LDO. This pin is input for detector. This pin is output for detector. GIN is an open-drain output. This pin is set by delay for detector. Please connect capacitor to GND for delay time. This pin is set by delay for gate slop start time. This pin is input for gate slop timing. This pin is controlled gate slop voltage by external resistance. This pin is output for gate slop. This pin is input supply for gate slop circuit. This pin is feedback input for positive charge pump. This pin is output for positive charge pump. This pin is input supply for operational amplifier, positive charge pump. This pin is output of operational amplifier. This pin is the non-inverting input of operational amplifier. This pin is the boost converter error amplifier output. Please connect resistance and capacitor to GND for phase compensation. This pin is feedback input for boost converter. Low level voltage is 640kHz, high level voltage is 1.2MHz. Power ground of boost converter. GND EXP should be soldered to GND to improve the thermal characteristics. Copyright© 2013 THine Electronics, Inc. All rights reserved. 3/12 THine Electronics, Inc. THV6520_Rev.1.00_E Electrical Characteristics Parameter （at VCC＝3.3V , Ta=25℃, unless otherwise noted） Symbol Test Conditions Min Typ Max Units System supply Input quiescent Current 1 Icc1 Vfb=1.35V(No switching) - 0.5 1 mA Input quiescent Current 2 Icc2 Vfb=1.1V(Switching) - 2 4 mA Standby current Ist Ven<0.8V - - 5 uA UVLO threshold voltage Vuvlo Vcc rising 1.8 2.0 2.2 V UVLO hysteresis voltage Vuvloh - 0.1 - V Vfb 1.228 1.240 1.252 V Ifb -40 0 40 nA Boost converter FB voltage FB input bias current Boost converter switching Fosc1 Vosc<(0.3xVcc) - 640 - kHz Fosc2 Vosc>(0.7xVcc) 1000 1200 1500 kHz Dmax 86 90 - % Oscillator pull down resistance Rosc - 250 - kΩ LX ON-resistance Ron1 - 200 500 mΩ LX current limit Ilim - 2.0 - A LX leakage current Ileak frequency 1 Boost converter switching frequency 2 Boost converter maximum duty cycle - - 0.1 uA Soft start charge current Iss Vlx=16V - 4 - uA FB short circuit voltage Vscp – 1.05 - V FB short circuit delay time Tscp - 160 - msec FBP voltage Vfbp 1.216 1.240 1.264 V FBP switching frequency Fosc3 - 1/2xFosc1 - kHz FBP short circuit voltage Vscp – 1.05 - V FBP high-side ON-resistance Ronh Vavdd=12V - 20 - Ω FBP low-side ON-resistance Ronl Vavdd=12V - 20 - Ω Iss - 4 - uA Vginh 1.5 - - V Charge pump Regulator FBP soft start Gate slop GIN input high voltage GIN input low voltage Vginl - - 0.6 V VGH to GOUT ON-resistance Rgouth - 30 - Ω GOUT to RE ON-resistance Rgoutl - 25 - Ω Delay set current Igdelay 18 20 22 uA Copyright© 2013 THine Electronics, Inc. All rights reserved. 4/12 THine Electronics, Inc. THV6520_Rev.1.00_E Parameter Buffer amplifier Symbol Test Conditions Min Typ Max Units AVDD quiescent Current Iavdd - 0.5 1.0 mA Input offset voltage Voff -17 - +17 mV Iamp_non - 1 50 nA Input bias current Input common-mode voltage Vamp_non 0.5 AVDD- - 0.5V AVDD- Output high voltage Vout_h Iamp=75mA - Output low voltage Vout_l Iamp=-75mA - 1.5 - V - 12 - V/usec Slew rate SR 1.5 - V V Short circuit high current Iamp_h Vamp_out=0V 90 140 180 mA Short circuit low current Iamp_l Vamp_out=AVDD 90 140 180 mA LDO LDO quiescent Current Iv_ldo – 90 - uA LDO FB voltage Vfb_ldo 1.224 1.240 1.256 V LDO current limit Ildo 350 500 - mA LDO dropout voltage dVldo Ildo=350mA - 350 500 mV LED load regulation dVldo2 Ildo=1mA to 300mA - - 0.5 % Detector Detector threshold voltage Vdet - 1.1 - V Detector hysteresis voltage Vdeth - 0.05 - V Detector ON-resistance Rdet Detector output delay time Trst DC=100nF Copyright© 2013 THine Electronics, Inc. All rights reserved. 5/12 - 50 - Ω - 12 - msec THine Electronics, Inc. THV6520_Rev.1.00_E current through the inductor equals to the current Function computed by the compensator. This loop acts within one Boost converter switching cycle. A slope compensation ramp is added to The LCD panel VLS supply is generated from a suppress sub-harmonic oscillations. An outer voltage high-efficiency PWM boost converter operating with feedback loop subtracts the voltage on the FB pin from current mode control, and the switching frequency is the internal reference voltage and feeds the difference to selectable between 640kHz and 1.2MHz. During the the compensator operational transconductance amplifier. on-period, TON, the synchronous FET connects one end This amplifier is compensated by an external R-C of the inductor to ground, therefore increasing the network to allow the user to optimize the transient inductor current. After the FET turns off, the inductor response and loop stability for the specific application switching node, LX, is charged to a positive voltage by conditions. the inductor current. The freewheeling diode turns on The output voltage VLS can be set by external resistor and the inductor current flows to the output capacitor. divider R1and R2 connected to FB. The converter operates in continuous conduction mode R VLS VFB 1 1 R2 when the load current IVLS is at least one-half of the inductor ripple current ΔIrip. I IN I rip I rip VLS 2 (VLS VIN ) VIN L FOSC VLS LX R1 FB The output voltage (VLS) is determined by the duty R2 cycle(D) of the power FET on-time and the input voltage, VIN. VLS VIN 1 D Fig. 1 FB setup The average load current, IVLS, can be calculated from [Compensator selection] the power conservation law. This current mode boost converter has a current sense VIN I IN VLS IVLS loop and a voltage feedback loop. The where η is the power conversion efficiency. For a lower loop does not need any load current, the inductor current would decay to zero feedback loop is during the free-wheeling period and the R-C network would be disconnected from the output node current sense compensation. The voltage compensated by an external series RPC and CPC from PC pin to ground. inductor for the RCOMP is set to define the high frequency integrator gain remaining portion of the switching period. The converter for loop bandwidth which relates to the transient would operate in the response. CPC is set to ensure the loop stability. discontinuous conduction mode . Current mode control is well known for its robustness and fast transient response. An inner current feedback [Output capacitor selection] loop sets the on-time and the duty cycle such that the The output voltage ripple due to converter switching is Copyright© 2013 THine Electronics, Inc. All rights reserved. 6/12 THine Electronics, Inc. THV6520_Rev.1.00_E determined by the output capacitor total capacitance, the largest possible while at the same time not degrading COUT, and the output VLS rip the maximum input and output current that the converter D I OUT I peak ESR FOSC COUT I peak I IN can operate with before reaching the current limit of the chip or the rated current of the inductor. I rip I peak I IN 2 The first ripple component can be reduced by increasing COUT. I rip 2 I MAX For example, ΔIrip could be set to 20% of IMAX Changing COUT may require adjustment of compensation R and C in order to provide adequate Voltage detector circuit phase margin and loop bandwidth. Voltage detector circuit senses the voltage on VDIN pin The second ripple component can be reduced by and turns on a pull-down FET that drives DOUT low if selecting low-ESR ceramic capacitors and using several VDIN voltage falls below the applicable threshold level smaller capacitors in parallel instead of just one large VDIN. When VDIN is rising, initially DOUT is pulled capacitor. low. As soon as VDIN exceeds (VDIN +VDIN), the reset timer is started. Once VDIN has remained above (VDIN +VDIN) for at least TD, the pull down FET opens and [Inductor selection] DOUT is driven high by an external pull-up resistor. To prevent magnetic saturation of the inductor core the During shut down, when VDIN falls below VDIN the inductor has to be rated for a maximum current larger pull down FET turns on and drives DOUT pin low. To than IPK in a given application. Since the chip provides current limit protection of 2A, it is the external voltage Vext, the rising and falling detection generally thresholds VDET,High and VDET,Low, respectively are set by recommended that the inductor be rated at least for 2A. the external voltage divider R3, R4. Selection of the inductor requires trade-off between the physical size (footprint x height) and its electrical VDet , High R4 R3 (VDin VDin ) R3 VDet , Low R4 R3 VDin R3 properties (current rating, inductance, resistance). Within a given footprint and height, an inductor with larger inductance typically comes with lower current rating and often larger series resistance. Larger inductance typically VIN requires more turns on the winding, a smaller core gap or a core material with a larger relative permeability. An inductor with a larger physical size has better electrical R3 properties than a smaller inductor. DIN It is desirable to reduce the ripple current ΔIrip in order to R4 reduce voltage noise on the input and output capacitors. In practice, the inductor is often much larger than the capacitors and it is easier and cheaper to increase the size of the capacitors. The ripple current Fig. 2 ΔIrip is then chosen Copyright© 2013 THine Electronics, Inc. All rights reserved. 7/12 Detector setup THine Electronics, Inc. THV6520_Rev.1.00_E The delay time is programmable by an external capacitor VLS as equation. For example, setting DC = 100nF can generate around 12ms delay for reset signal. TD = 120K x DC. VGH_OUT VGH VDETH Vext (VDIN+VDIN) VDIN VDETL R6 VGH_FB VDIN R5 VPC Fig. 4 VGH setup TD DOUT Gate slope Fig. 3 The Gate slope is a flicker compensation circuit to Detector timing chart reduce the coupling effect of gate lines, and is controlled by timing controller to modulate GOUT, the Gate-On Positive charge pump (VGH) voltage. This block is not activated until the below 3 The positive charge pump is used to generate the TFT conditions are satisfied: 1) The input voltage exceeds its LCD gate on voltage. The output voltage, VGH, can be UVLO, 2) No fault condition is detected, and 3) set by an external resistive divider. GDELAY exceeds its turn-on threshold. Once Gate slope Voltage VVGH_FB is typically 1.24V. A single stage activates and GIN is high, the internal switch between charge pump can produce an output voltage less than V_VGH and GOUT turns on and the switch between approximately twice the charge pump input voltage VLS. GOUT and GR turns off. If GIN is low, the internal The charge pump can deliver up to 20mA of current. The switch between V_VGH and GOUT turns off and the maximum voltage VGH should not exceed 38V if it is switch between GOUT and GR turns on. At that time, used to supply the Gate slope circuit. The output voltage the falling time and delay time of the Gate-On voltage VGH is regulated as the following equation. are programmable by an external resistor connected between GR and GND. VGH VVGH _ FB R5 R6 R5 VCOM buffer The VCOM buffer generates the bias supply for the back plane of an LCD screen which is capacitively coupled to the pixel drive voltage. The purpose of the VCOM buffer is to hold the bias voltage steady while pixel voltage changes dynamically. The buffer is designed to sustain Copyright© 2013 THine Electronics, Inc. All rights reserved. 8/12 THine Electronics, Inc. THV6520_Rev.1.00_E up to ±75mA of output current. In transients, it can deliver up to 150mA at which point the over current Soft start (SS) protection circuit limits the output current. Excessive The boost converter carries the soft start function in current draw over a period of time may cause the chip order to prevent the rush current at a start-up. This temperature to rise and set off the over temperature function is to raise output voltage slowly. It is because protection circuit. overshooting and rush current occur when input voltage is inputted. When power is turned on, an internal 4μA current source charges an external capacitor connected as LDO SS. When power is turned off, the external capacitor will The THV6520 has a integrated LDO which can supply be discharged for the next soft start cycle. up to 350mA current while the input voltage is 3.3V. It is suitable for the supply voltage to timing controller and source IC. Over voltage protection (OVP) Over voltage protection is built in. If VLS is disconnecting, the output voltage of a boost converter is Protection circuits stopped and destruction of IC is prevented. Under voltage lock out protection (UVLO) The UVLO function is carried in order to prevent malfunction in the state where input voltage is low. A Over current protection (OCP) boost converter is suspended to the power supply voltage In order to restrict the over-current by the abnormalities which can carry out operational stability. UVLO is of load, etc., the over-current protection circuit is built in. released by more than 1.8V input voltage. And a boost Over-current detection of pulse-by-pulse system is converter carries out, after starting soft start operation. adopted. An output transistor is turned off if the current During steady-state operation, if the output of the boost which flows into an output transistor reaches boost converter is under 85% of the nominal value, the converter limit current (Ilim). An over-current protection THL6520 activates an internal fault timer. If any circuit detects the peak current of an inductor. condition indicates a continuous fault for the fault timer Input-and-output voltage and ripple current is taken into duration (160ms typ), the IC sets the fault latch to shut consideration. down all its output. Once the fault condition is removed, cycle the VIN (below the UVLO falling threshold) to clear the fault latch and reactivate the device. The Thermal shut down (TSD) fault-detection circuit is disabled during the soft-start In order to prevent destruction by heat, the thermal ramp. shutdown circuit is built in. If the junction temperature Tj is 150oC or more, the thermal shutdown circuit will operate and it will stop switching operation. Moreover, the hysteresis of a thermal shutdown circuit is 15oC. If Tj falls, output voltage will return. Copyright© 2013 THine Electronics, Inc. All rights reserved. 9/12 THine Electronics, Inc. THV6520_Rev.1.00_E Package Dimensions QFN 24-pin Recommend connecting Back Exposed Pad with GND for a thermal characteristic improvement. Copyright© 2013 THine Electronics, Inc. All rights reserved. 10/12 THine Electronics, Inc. THV6520_Rev.1.00_E Notices and Requests 1. The product specifications described in this material are subject to change without prior notice. 2. The circuit diagrams described in this material are examples of the application which may not always apply to the customer’s design. We are not responsible for possible errors and omissions in this material. Please note if errors or omissions should be found in this material, we may not be able to correct them immediately. 3. This material contains our copyright, know-how or other proprietary. Copying or disclosing to third parties the contents of this material without our prior permission is prohibited. 4. Note that if infringement of any third party's industrial ownership should occur by using this product, we will be exempted from the responsibility unless it directly relates to the production process or functions of the product. 5. This product is presumed to be used for general electric equipment, not for the applications which require very high reliability (including medical equipment directly concerning people's life, aerospace equipment, or nuclear control equipment). Also, when using this product for the equipment concerned with the control and safety of the transportation means, the traffic signal equipment, or various Types of safety equipment, please do it after applying appropriate measures to the product. 6. Despite our utmost efforts to improve the quality and reliability of the product, faults will occur with a certain small probability, which is inevitable to a semi-conductor product. Therefore, you are encouraged to have sufficiently redundant or error preventive design applied to the use of the product so as not to have our product cause any social or public damage. 7. Please note that this product is not designed to be radiation-proof. 8. Customers are asked, if required, to judge by themselves if this product falls under the category of strategic goods under the Foreign Exchange and Foreign Trade Control Law. 9. The product or peripheral parts may be damaged by a surge in voltage over the absolute maximum ratings or malfunction, if pins of the product are shorted by such as foreign substance. The damageｓ may cause a smoking and ignition. Therefore, you are encouraged to implement safety measures by adding protection devices, such as fuses. THine Electronics, Inc. [email protected] Copyright© 2013 THine Electronics, Inc. All rights reserved. 11/12 THine Electronics, Inc.