Abstract: Philips using EZ-HV SOI process manufacturing UBA2032T/TS full-bridge driver can be used to drive any type of load, especially suitable for driving HID lamps. This paper introduces UBA2032T/TS's features, given its typical application circuit.

Key words: full-bridge driver; high IC; UBA2032T/TS; HID lamp driving circuit

1 Overview

Philips has introduced high-voltage monolithic IC is used UBA2032 EZ-HV SO1 manufacturing process of a high-voltage full-bridge driver. UBA2032 in full-bridge topology can drive through any of the external MOSFET load, especially suitable for driving high-intensity discharge  HID   such as high pressure sodium lamps and metal halide  commutator so  commutator . UBA2032 The main features are as follows:

● Built-in bootstrap diode and high-voltage level shifter;

● bridge voltages up to 550V, and direct input from the IC's HV feet high, the internal circuitry that produces low voltage, low voltage without the need for additional power;

● Start with input time delay, a simple RC filter can be used or from the delayed control signal processor;

● oscillator frequency can be adjusted;

● As long as BD foot bridge cut-off threshold voltage exceeds  1.29V , all MOSFET will be turned off;

● To ensure 50% duty cycle, the oscillator signal is fed to the output drivers to be passed before the divider;

● non-overlapping  non-overlap  time adaptive non overlap control circuit may be the minimum non-overlap time can be in the internal fixation;

● 24-pin SO package  UBA2032T  28-pin SSOP package and  UBA2032TS , pinout shown in Figure 1.

Block diagram of the internal structure of Figure 2 UBA2C32T/TS Click to enlarge

2 internal structure and working principle

2.1 The internal structure and the pin function

UBA2032 chip integrated voltage regulator, oscillator, input signal delay and the bridge prohibiting circuit, control logic, high / low voltage level shifter, high-end left / right drive and low left / right drive, and other cell circuit, Figure 2 shows the block diagram of its internal structure. Table 1 lists the various pin functions are UBA2032.

Pin Function Table 1 UBA2032

Symbol Pin Function

UBA2032TUBA2032TS

-LVS11 negative supply voltage logic input

EXTRD22 oscillator signal input

+ LVS33 logic inputs positive supply voltage

n.c4, 6,16,19,214,5,7,18,19,22,24,25 empty legs

HV56 internal low power supply voltage generated pin

Internal low power supply voltage VDD79

SU810 start delay the input signal

DD911 divider control input prohibited

BD1012 bridge control input prohibited

RC1113 internal RC oscillator input

SGND1214 signal ground

GHL1315 MOSFET gate on the left end

FSL1416 left floating supply voltage

SHL1517 top left of the MOSFET source

GLL1720 left side MOSFET gate low

PGND1921 power to

GLR2023 right side MOSFET gate low

SHR2226 top right of the MOSFET source

FSR2327 right side floating supply voltage

GHR2428 MOSFET gate on the right end

Table 2 logic

The device state input (pin) output (pin)

BDSUDDEXTDRGHLGHRGLLGLR

Start HXXXLLLL

LXXXLLHH

Oscillation HXXXLLLL

LLXXLLHH

LHHGLHHL

LHLLH

LHLLHLLH

LHHLLH

HHLLH

HLLHHL

Note: H is high; L low; X that has nothing to do

2.2 Work

UBA2032 both feet from the HV voltage is applied to generate the internal low power supply voltage VDD  11.5 ± 2V , low voltage power supply can also be directly connected to the VDD pin  this case pin HV pin must be connected to VDD or SGND . When the VDD pin voltage is higher than the feet or the release of HV power drive level  typical 9V and 12.5V  respectively, the bridge output voltage control signal will be EXTDR feet to a decision. Table 2 lists the IC's state and input / output between the logic. Once the VDD pin voltage drops on or HV power driver reset level  6.5V and 10V  were the following, IC will enter again to start the state.

When the pin voltage through the release of HV power drive level, the bridge will be determined according to the state for the following two points:

(1) high-end left and right side MOSFET turns on low-end, high-end cut-off on the right and low left of the MOSFET;

(2) high-end left and right side MOSFET low-end, high and low on the left of the right side MOSFET conduction.

UBA2032 can oscillate in three different modes:

The first is the internal oscillator mode. In this mode, the bridge switching frequency by an external resistor and capacitor COSC ROSC to decide. To achieve 50% duty cycle, the internal divider by connecting pins should be assigned to DD to SGND pin EXTDR  must also foot + LVS,-LVS and SGND or VDD together.

The second is the internal divider without external oscillator mode. In this mode, the pin to SGND will enable the internal RC oscillator circuit cut-off. When an external signal source is connected to pin EXTRD, the bridge frequency is equal to the external oscillator frequency, rather than as an internal oscillator mode, the internal oscillator frequency bridge frequency is 1 / 2.

The third type is the internal divider of the external oscillator mode. In this mode, in order to make the internal division is enabled, pin RC, DD and feet SGND must be connected together, and then full-bridge output frequency of the external oscillator frequency of 1 / 2 bridge for the pin through the EXTRD falling edge trigger signal.

Application Circuit 3

3.1 HID lamp base drive circuit

UBA2032 to drive HID lamps primarily designed, as shown in Figure 3 is composed of HID lamps UBA2032T full-bridge driver circuit. In this basic application topology, IC of the bridge against, start delay, and no external drive feature to be used, IC pin-LVS, + LVS, EXTDR and BD are shorted to SGND. DD pin connected to SGND, within 2 frequency divider is enabled. The use of an internal oscillator, bridge replacement and COSC ROSC to the frequency values can be determined:

fbridge = 1 /  Kosc.Rosc.Cosc 

Where constant Kosc 1.02. When the voltage on the IC pin HV than 12.5V (typical value) (when the oscillator to work. Once the voltage on pin HV down to 10V (typical value) the following, then, UBA2032T will enter the startup state.

Such as high pressure sodium HID lamps, usually 3 ~ 6kV high-voltage pulse to enable it to start the ignition. Therefore, in the full-bridge driver circuit, it should start   additional ignition circuit. In ordinary fluorescent lamp electronic ballasts, the light starts normally use in the LC series resonance across the capacitor produces a more than 1kV applied to the lamp on high, so that breakdown and lit the lamp. The HID lights starting circuit is usually a negative resistance characteristics of the switching elements (such as silicon AC-way switch), capacitors and inductors and other boost components, the circuit can be used to generate several thousand volts of high voltage ignition pulse.

 

3.2 headlights Driver

Depends on the life of HID lamps light through the quartz wall of the sodium mobility.Therefore, in order to minimize the mobility of sodium lamps to extend the service life, HID lamps can be compared to the negative voltage for the system to operate. Figure 4 shows the headlights (HID lights) full-bridge driver circuit. The circuit UBA2032TS feet + LVS and the HV control circuit with the bridge to impose the same low supply voltage, pin-LVS is connected to system ground. The system for reference, the bridge maximum in-450V   negative voltage operation, while "H" bridge and the IC output state control signals on foot ESTDR relevant.Thus, in the HID lamp ignition, the circuit will produce a very large EMC spikes, while in full-bridge MOSFET (LL, LR, HR and HL) of the gate will produce very high transient voltage or oscillations. When the MOSFET gate directly to the output driver IC output (pin GHR, GHL, GHL, and GLL) direct coupling, the drive will produce the output voltage over shocks. To reduce the stress off the driver output can be in series with each MOSFET gate a minimum of not less than 100Ω resistor and a parallel high-speed switching diode (such as the IN4148).

If each MOSFET gate charge for the QG, then when the bridge frequency fbridge, the four total MOSFET gate current IG is 4fbrigeQG. The current low-voltage power supply can be internal (VDD) to provide. Provided the VDD internal protection circuit maximum current limit is 11mA, so, in order to prevent the current shortage of supply, the design should add a secondary low-voltage power supply. UBA2032 there are similar devices such as U-BA2030 and UBA2033.