1 Introduction
The UBA2030T, manufactured by Philips using the BCD750 power logic process, is a high voltage IC specifically designed to drive power MOSFETs in a full-bridge topology. The UBA2030T can be used to form high-intensity discharge (HID) lamp electronic ballast circuits with a small number of external components and provides a solution for the design of HID lamp drive circuits.
2 package, internal structure and pin function
The UBA2030T is available in a 24-pin SO package. The top view is shown in Figure 1.
The UBA2030T chip integrates bootstrap diodes, oscillators, high voltage and low voltage phase shifters, high-end (left, right) and low-end (left and right) drivers and control logic. The internal block diagram is shown in Figure 2.
Table 1 lists the pin functions of the UBA2030T.
2 main parameters and characteristics
2.1 main parameters
The main parameters and reference data of UBA2030T are listed in Table 2.
2.2 main features
Figure 1 SO24 package top view
The main features of the UBA2030T are as follows:
Built-in bootstrap diode for driving full-bridge circuitry to minimize external components;
High voltage input up to 570V for driving internal circuitry and full bridge
Figure 2 Internal block diagram of UBA2030T
Table 1 Pin Function Pin No. Symbol Description 1 GLR Low-Side Right MOSFET Gate Driver Output 2 PGND Low-End Left and Right MOSFET Source Power Ground 3 GLL Low-End Left MOSFET Gate Driver Output 4,6,9 ,16,17,19 nc not connected 5 RC internal oscillator RC input 7 BE control input enable 8 BER bridge reference input enable 10 FSL floating supply voltage left output 11 GHL high end left MOSFET gate driver output 12 SHL high end Left MOSFET Source 13 SHR High Side Right MOSFET Source 14 GHR High Side Right MOSFET Gate Driver Output 15 FSR Floating Supply Voltage Right Output 18 HV High Voltage Power Input 20 EXO External Oscillator Input 21 SD Off Input 22 DTC Dead Time Control Input 23 VDD Internal (Low Voltage) Power Supply 24 SGND Signal Ground
Table 2 main parameters and reference data
Symbol parameter condition minimum value typical value maximum unit
 VDD range: 0V ~ 18V
In the MOSFET, the IC provides its own low supply voltage;
The dead time tdead is set by the resistor RDT connected between the DTC pin and the SGND pin, and RDT=270tdead-70, RDT(min)=50kΩ, RDT(max)=1MΩ (when the unit of the RDT is kΩ, The unit of tdead is μs);
The oscillator frequency is adjustable. When using the internal oscillator, the bridge frequency can be set with the external resistor ROSC and capacitor COSC: fbridge=1/(2×8×ROSC×COSC) and requires ROSC=200kΩ. ~2MΩ;
Built-in PMOS high voltage phase shifter to control the bridge enable function;
With a shutdown function, as long as the input on the SD pin reaches 4.5V, the four MOSFETs in the full bridge are turned off.
3 application introduction
Typical applications for the UBA2030T are primarily full-bridge drivers in HID lamp electronic ballast circuits such as high voltage (HPS) lamps and metal halide lamps.
3.1 basic application circuit
The basic topology of the full bridge using the UBA2030T as the driver and the HID lamp as the load is shown in Figure 3. In this application circuit,
Figure 3 UBA2030T as the driver, HID lamp is the full bridge basic circuit of the load
Figure 4 HID lamp full bridge topology with external control circuit
Figure 5 shows the HID lamp driver circuit of the control circuit with the high end of the bridge as a reference.
Figure 6 uses a low voltage DC power supply for internal circuitry
HID lamp full bridge driver circuit providing current
The BER pin, BE pin, EXO pin and SD pin are all connected to the system ground, and the bridge enable and disable functions are not used. When using the internal oscillator, the bridge commutation frequency is determined by the values ​​of ROSC and COSC. When the HV applied voltage exceeds the oscillation trigger threshold (typically 15.5V), the oscillator begins to oscillate. If the voltage on the HV pin drops to the oscillator stop threshold (typically 13V), the IC will re-enter the startup state.
Once the IC starts to work normally, HR(Q3) and LL(Q2) are turned off when the power switches HL(Q1) and LR(Q4) are turned on; when HR(Q3) and LL(Q2) are turned on, HL( Q1) and LR (Q4) are closed. The commutation logic provided by the UBA2030T ensures that alternating current can be generated in the HID lamp.
The activation of the HID lamp requires the application of a high voltage pulse of 3kV to 10kV. An igniter circuit consisting of a trigger element with a negative resistance characteristic, a capacitor and a booster coil, etc., can generate a high voltage sufficient to break down the HID lamp after energization, causing the lamp to ignite. In order to prevent the acoustic resonance phenomenon of the HID lamp, the arc is unstable and the lamp tube is burned out. For the HID lamp driving circuit, the acoustic resonance suppression measures are often taken.
3.2 Application Circuit with External Oscillator Control
Figure 4 shows the HID lamp full bridge topology with an external oscillator control circuit. In this application circuit, the RC pin, BER pin and BE pin of the UBA2030T are connected to the system ground. The bridge commutation frequency is determined by the external oscillator. The off input pin (SD pin) can be used to turn off all MOSFETs in the full bridge circuit. .
3.3 Control circuit HID lamp full bridge driver circuit with high bridge reference
The UBA2030T is used as a commutator component in driving a HID lamp full bridge system. The service life of HID lamps depends on the amount of sodium migration through the quartz walls. In order to minimize the sodium migration ratio, the HID lamp must be operated under negative pressure when it is systematically referenced. Figure 5 shows the HID lamp full bridge driver circuit with the control unit referenced to the high end of the bridge. In this application circuit, both the BER pin and the HV pin are connected to the system ground.
Another HID lamp full bridge driving circuit with a high end of the bridge as reference is shown in FIG. The BER pin is connected to the ground. The current flowing into the IC's internal low-voltage circuit through the HV pin can be supplied by a low-voltage DC power supply (such as a battery), as shown by the dashed line in FIG. The value of RDT is between 50kΩ and 1000kΩ. When RDT = 220KΩ, the dead time tdead is 1μs.
In any application, the voltage on the IC pin HV cannot be lower than the voltage on the VDD pin. Otherwise, the full bridge will not work correctly whether it is in the startup state or during normal operation. During the startup phase, the EXO pin and SD pin of the IC should be at a low level. When the voltage of the EXO pin and the SD pin is a function of time, the rate of change should be greater than 5V/ms.
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