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AN10907

All information provided in this document is subject to legal disclaimers.

Application note

Rev. 1 — 28 December 2010

33 of 82

NXP Semiconductors

AN10907

TEA1613T resonant power supply control IC

CMR of the TEA1613T can be recognized by the typical slowing of the oscillator in
combination with the discharging of SSHBC/EN.

Fig 19. Capacitive/inductive HBC operating frequencies

001aal443

load independent point
(series resonance)

@ Vimax

@ Qmax

@ Qnom

@ Qmin

@ Vinom

@ Vimin

Mmin

Mnom

Mmax

resistive

inductive

capactive

fmax

M =

a·V

Note: Oscilloscope traces contain normal time-base (top) and zoomed view (bottom)

Fig 20. Typical protection and regulation behavior in capacitive mode (during bad start-up)

001aal444

Typical behavior at capacitive
mode protection/regulation

Frequency increase by capacitive
mode protection/regulation
(notice voltage drop on SSHBC/EN)

SNSCURHBC

SSHBC/EN

Voutput

CFMIN

SSHBC/EN

Voutput

Содержание AN10907

Страница 1: ...level shift circuit and several protection features like over current protection open loop protection capacitive mode protection and a general purpose latched protection input In addition to the norma...

Страница 2: ...nt is subject to legal disclaimers NXP B V 2010 All rights reserved Application note Rev 1 28 December 2010 2 of 82 NXP Semiconductors AN10907 TEA1613T resonant power supply control IC Revision histor...

Страница 3: ...thin the application note and to descriptions or figures that are similar to the ones published in the TEA1613T data sheet In most cases typical values are given to enhance the readability Section 1 I...

Страница 4: ...th Modulated PWM power converters such as flyback up and down converters are widely used in low and medium power applications A disadvantage of these converters is that the PWM rectangular voltage and...

Страница 5: ...otection or external temperature protection Protection timer for time out and restart Overtemperature protection Soft re start Under voltage protection for boost brownout IC supply and output voltage...

Страница 6: ...1 5 k internally connected to 8 4 V results in the regulation voltage The regulation voltage range is from 4 1 V to 6 4 V and corresponds with the maximum and minimum frequency that can be controlled...

Страница 7: ...connected to the boost voltage SUPIC and SUPREG are charged with a constant current by the internal start up source SUPHV operates at a voltage above 25 V Initially the charging current is low 1 1 mA...

Страница 8: ...on RFMAX can vary between 0 V minimum frequency and 2 5 V maximum frequency The RFMAX voltage running frequency is driven by SNSFB and SSHBC EN function The protection timer is started when the voltag...

Страница 9: ...provided in this document is subject to legal disclaimers NXP B V 2010 All rights reserved Application note Rev 1 28 December 2010 9 of 82 NXP Semiconductors AN10907 TEA1613T resonant power supply co...

Страница 10: ...UP SOURCE CONTROL 10 9 V 5 5 mA SUPIC SuplcShort LatchReset 0 65 V 7 V 1 6 V 50 mV SupReg EnableSupReg reduced current startlevel Hv 22 V startlevel Lv 17 V stoplevel 15 V SupRegUvStart startlevel 10...

Страница 11: ...inal VBoost no compensation nominal OCP nominal VBoost no compensation nominal OCR VSNSCURHBC t t VSNSCURHBC Vocr HBC Vocr HBC Vocp HBC Vocp HBC 0 A 0 V 1 8 V VSNSBOOST Icompensation on SNSCURHBC 2 5...

Страница 12: ...and GATEHS To supply GATEHS a bootstrap function with an external diode is used to make supply SUPHS SUPIC and SUPREG also supply other internal TEA1613T circuits 6 1 2 Supply monitoring and protectio...

Страница 13: ...e IC is continuously supplied by the external DC supply For this kind of application the SUPHV pin should be left open 6 2 2 SUPIC stop UVP and short circuit protection The IC stops operating when the...

Страница 14: ...ation in the HV start up source when SUPIC is shorted to ground During normal conditions SUPIC quickly exceeds the protection level and the HV start up source switches to normal current 5 1 mA The HV...

Страница 15: ...sformer construction 6 3 3 1 SUPIC and SNSOUT PFCON by auxiliary winding The SNSOUT PFCON input provides a combination of 3 functions Overvoltage protection SNSOUT PFCON 3 5 V latched Undervoltage pro...

Страница 16: ...s at higher output currents due to the higher currents causing a larger voltage drop across the series components An auxiliary winding supply shows this variation caused by the HBC output 6 3 3 3 Volt...

Страница 17: ...voltage 6 4 1 Start up When the TEA1613T is supplied by an external DC supply the SUPHV pin can be left unconnected The SUPIC start level is now 17 V When the SUPIC exceeds 17 V the internal regulato...

Страница 18: ...he IC stops operating to prevent unreliable switching due to a too low gate driver voltage The HBC continues until the low side stroke is active The maximum current from the internal SUPREG series sta...

Страница 19: ...hen SUPIC 22 V When start up is by an external low voltage supply SUPREG is activated when SUPIC 17 V 6 5 3 Supply voltage for the output drivers SUPREG The TEA1613T has a powerful output stage for GA...

Страница 20: ...amount of gate charge and or when switching at high frequencies Instead of using SUPREG as the power source for charging SUPHS another supply source can be used In such a construction it is important...

Страница 21: ...it supplied by SUPHS slowly discharges the supply voltage capacitor At the moment a new burst starts the SUPHS voltage is lower than during normal operation During the first switching cycles the SUPHS...

Страница 22: ...mA ISUPREG_for_IC With respect to the IC by far the most amount of current from SUPREG is consumed by the MOSFET drivers GATELS and GATEHS Other circuit parts in the IC consume a maximum of 4 mA ISUP...

Страница 23: ...mple provides an estimation and not an exact calculation ISUPIC start up 10 mA VSUPIC start up 22 V 15 V 7 V tVaux 15V 70 ms 1 6 6 1 3 Normal operation For normal operation the main purpose of the cap...

Страница 24: ...or on SUPREG should be much larger than the total capacitance of the MOSFETs that need to be driven including the load and capacitor on SUPHS that is in parallel with the bootstrap construction to pre...

Страница 25: ...connection to the midpoint of the external half bridge The high side driver is supplied by a capacitor on SUPHS that is supplied by an external bootstrap function by SUPREG The capacitor on SUPHS is c...

Страница 26: ...acitance to be discharged the voltage on the gate just before discharge the gate threshold voltage for the MOSFET to switch off the external circuit to the gate Because the timing for switching off th...

Страница 27: ...The value of the source current is highest when the supply voltage is highest and the gate voltage 0 V The value of the sink current is highest when the gate voltage is highest The supply voltage pro...

Страница 28: ...is on The start level is determined by an internal hysteresis current source of 3 A in combination with the resistance values of the external divider The boost voltage for starting is higher than the...

Страница 29: ...vel has an effect on the amount of compensation current in SNSBURST For information relating to combining both functions see Section 9 5 2 Advanced design of SNSBURST circuit 8 2 HBC switch control Th...

Страница 30: ...ank has an inductive impedance The time required for the transition of the HB depends on the amplitude of the resonant current at the moment of switching There is a complex relationship between the am...

Страница 31: ...5 of HB switching period the MOSFET is forced to switch on In this case the MOSFET is not soft switching This limitation of the maximum non overlap time ensures that at very high switching frequency t...

Страница 32: ...el To bring the converter from capacitive mode to inductive operation again the oscillation frequency is increased by the capacitive mode regulation function 8 3 3 Capacitive Mode Regulation CMR The h...

Страница 33: ...e inductive HBC operating frequencies 001aal443 load independent point series resonance fo Vimax Qmax Qnom Qmin Vinom Vimin Mmin Mnom 1 Mmax resistive inductive capactive fl fr fmax f M Vi a Vo Note O...

Страница 34: ...um The voltage on RFMAX is 2 5 V when the oscillator frequency is maximum The value of the resistor on RFMAX determines the relationship between VRFMAX and the frequency It also determines the maximum...

Страница 35: ...nd the other one on is adaptive non overlap time or dead time This non overlap time has no influence on the oscillator signal The frequency control by oscillator frequency consists of determining the...

Страница 36: ...or is 4 7 There is a small deviation in value depending on other parameters and presetting conditions Practical verification of the result is advised CFMIN Ioscillator min 2 2 fHB min Voscillator 150...

Страница 37: ...1 5 V 8 5 HBC feedback SNSFB A typical power supply application contains mains insulation in the HBC On the secondary mains insulated side the output voltage is compared to a reference and amplified...

Страница 38: ...an 260 A which leads to an open loop protection Burst mode and open loop protection To implement a burst mode a resistor divider is connected between SNSFB and ground The impedance of this resistor di...

Страница 39: ...6 1 Switching on and off using an external control function The SSHBC EN can be used to switch the converters on and off using an external control function This function is often driven by a microcont...

Страница 40: ...SSHBC EN with the main difference being that HBC continues without soft start For more details on burst mode operation see Section 9 1 8 6 2 Soft start HBC The soft start function for the resonant co...

Страница 41: ...s also used for regulation purposes such as over current regulation Therefore the voltage on the capacitor on SSHBC EN can vary by charging and discharging it by internal current sources For example i...

Страница 42: ...is dominant to provide protection and soft start capability In addition there is an internal soft start reset mechanism that overrules both SNSFB and SSHBC EN control inputs and immediately sets the f...

Страница 43: ...8 7 Overcurrent protection and regulation HBC Measurement of the primary resonant current indicates the level of output power that is being generated by the converter In case of a fault or output over...

Страница 44: ...frequency is slowly increased until the resonant current value just reaches the value permitted by the preset The behavior during OCR can be observed on the SSHBC EN pin as a resultant regulation vol...

Страница 45: ...during OCP can be observed on the SSHBC EN pin as a new soft start Depending on the over load or fault condition during this new soft start OCR or OCP can be activated again 8 7 3 SNSCURHBC boost volt...

Страница 46: ...l cycle by cycle at higher frequencies it is susceptible to disturbances To prevent disturbances on this input the series resistor Rcc should be placed close to the IC to reduce the length of the trac...

Страница 47: ...he output voltage This deliberately creates a small ripple on the output voltage during burst mode 9 1 Burst mode implementation Burst mode can be Implemented by a resistance divider from SNSFB to gro...

Страница 48: ...cy in low load conditions The SNSOUT PFCON provides an on off switching signal that can be used to stop and start the PFC This signal switches between the voltage level for output voltage monitoring 2...

Страница 49: ...ter is to improve the efficiency at low output power by reducing the power losses The graphs in Figure 34 and Figure 35 show the principle improvements in a 250 W resonant converter including non burs...

Страница 50: ...the burst period the power is transferred directly from the input to the output The HBC determines the repetition time of the burst and the PFC follows In the burst period the PFC operates in normal r...

Страница 51: ...sen experimentally 9 5 1 Basic design of an SNSBURST circuit The SNSFB voltage level at which the converter enters burst mode can be chosen by a resistor divider This voltage value can be adapted to c...

Страница 52: ...t burst level for variations in the boost voltage The impedance of the resistor divider determines the amount of compensation The higher the impedance the stronger the compensation is Remarks Note tha...

Страница 53: ...nd SNSBURST regarding the compensation design the calculation sheet can used The sheet provides more details and the possibility to visualize the result of value variation In the calculation sheet an...

Страница 54: ...me as the example in Section 9 5 2 VSNSFB 27 28 Choose the value of RSBURST to obtain the same compensation as in example Section 9 5 2 indicator gave 72 Hz V Because the relationships are complex the...

Страница 55: ...y that it cannot regulate to no load even at the highest frequency During the lowest loads the required frequency for regulation must become infinite Because the characteristic is much steeper for low...

Страница 56: ...much to generate audible noise The magnetization current however is still present during low loads and is the dominant energy during burst mode Switching on and off the converter sequences continuous...

Страница 57: ...ernal PFC the signal from pin SNSOUT PFCON can be used The behavior of the total system PFC and resonant in burst mode may differ from the situation when only the resonant converter operates in burst...

Страница 58: ...level and hysteresis System and component tolerances play a significant role in performance variations during production The regulation feedback loop can be optimized for normal mode and any additiona...

Страница 59: ...Resetting a latched protection shutdown state When a latched protection shutdown state has occurred this state is reset by one of the following actions SUPIC drops below 7 V and SUPHV is lower than 7...

Страница 60: ...er construction is needed To facilitate correct working it is important that this winding has a good coupling with the secondary winding s and a minimum coupling with the primary winding In this way a...

Страница 61: ...UT PFCON voltage drops below 2 35 V When detecting UVP the TEA1613T starts the protection timer by charging it with 100 A When the undervoltage state remains until the timer reaches the protection lev...

Страница 62: ...e so that the OVP is still functional 10 3 3 3 UVP functionality and OVP disabled In some applications it may be required to prevent the activation of the OVP on SNSOUT PFCON To achieve this it is nec...

Страница 63: ...urst mode operation When the system is in burst mode operation the undervoltage protection is not active while switching is off This is to prevent incorrect protection during this interval As soon as...

Страница 64: ...n The values for both types of timer can be independently preset by an external resistor and capacitor connected to RCPROT 10 4 1 Block diagram of the RCPROT function 10 4 1 1 RCPROT working as protec...

Страница 65: ...op protection SNSFB undervoltage protection SNSOUT PFCON Protection can be forcibly activated including restart by increasing the RCPROT voltage to above 4 V but not higher than 12 V using an external...

Страница 66: ...required restart time trestart determines the time constant tRCPROT made by the values of R and C 29 With this time constant and the required protection time tprotection the value of R and C can be ca...

Страница 67: ...ground plane if possible to avoid false signal detection by driver current disturbance see Figure 54 A star grounding construction provides the lowest risk of mutual converter disturbance or signal de...

Страница 68: ...NSCURHBC connection as close as possible to pin 15 This is important for avoiding disturbance pickup Also avoid capacitive coupling between the connection to pin 15 and the HB track to pin 13 that con...

Страница 69: ...with protection disabled 2 HBC with protection disabled and variable DC input voltage 3 HBC with protection enabled The best approach is to check the HBC converter first with external supplies for SUP...

Страница 70: ...t VBOOST 0 V the running frequency is low with a short on time and a long off time This is due to the HB detection not working properly at low voltage and the internal slope detection HB not detecting...

Страница 71: ...se voltage if needed SNSOUT PFCON 1 20 RCPROT TEA1613 SNSFB 2 19 SSHBC EN SNSBURST 3 18 RFMAX SNSBOOST 4 17 CFMIN SUPIC 5 16 SGND PGND 6 15 SNSCURHBC SUPREG 7 14 n c GATELS 8 13 HB n c 9 12 SUPHS SUPH...

Страница 72: ...e is zero input voltage it indicates that the connection between these pins directly at the IC is not present Gate currents lead to false HB slope detection SNSCURHBC Any disturbances on this pin volt...

Страница 73: ...nal not defective evaluate specific IC function s or pin properties with limited interference from the total system Fig 57 Example of a basic IC test setup on a single low voltage supply 24 V 019aaa26...

Страница 74: ...mber 2010 74 of 82 NXP Semiconductors AN10907 TEA1613T resonant power supply control IC 12 2 Example of a 250 W LCD TV application Fig 58 Example of a 250 W LCD TV application part 1 019aaa265 L CN101...

Страница 75: ...302 12N50C3 R357 100 k R132 4 7 M R135 62 k R133 4 7 M R134 51 k R355 10 R352 51 D351 1N4148 D365 BAS316 R353 100 k R310 8 2 R361 51 k R362 n m R351 10 C326 560 nF C328 10 nF C308 680 nF C306 680 nF C...

Страница 76: ...v 1 28 December 2010 76 of 82 NXP Semiconductors AN10907 TEA1613T resonant power supply control IC Fig 60 Example of a 250 W LCD TV application part 3 019aaa267 D201 1N4007 D202 1N4148 ZD201 30 V C206...

Страница 77: ...02 12N50C3 R357 100 k R132 4 7 M R135 62 k R133 4 7 M R134 51 k R355 10 R352 51 D351 1N4148 D365 BAS316 R353 100 k R310 8 2 R361 51 k R362 n m R351 10 C326 560 nF C328 10 nF C308 680 nF C306 680 nF C3...

Страница 78: ...atibility EMI ElectroMagnetic Interference or Immunity HB Half Bridge HBC HalfBridge Converter or Controller HFP High Frequency Protection HV High Voltage IC Integrated Circuit LCD Liquid Crystal Disp...

Страница 79: ...applications and products using NXP Semiconductors products and NXP Semiconductors accepts no liability for any assistance with applications or customer product design It is customer s sole responsibi...

Страница 80: ...art up 42 Fig 29 Soft start reset and two speed soft start 43 Fig 30 OCP and regulation HBC 44 Fig 31 SNSCURHBC resonant current measurement configurations 46 Fig 32 Principle of burst mode operation...

Страница 81: ...utput drivers SUPHS 20 6 5 4 1 Initial charging of SUPHS 20 6 5 4 2 Current load on SUPHS 20 6 5 4 3 Lower voltage on SUPHS 21 6 5 5 SUPREG power consumed by MOSFET drivers 21 6 5 6 SUPREG supply volt...

Страница 82: ...normal operation 57 9 9 4 Audible noise during mode transition 58 9 10 Design guidelines for burst mode operation 58 9 11 Enable disable burst mode 58 9 12 Hold HBC and PFC 58 9 13 Unused burst mode 5...

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