High-performance, low-saturated linear regulator (LDO) development

The whole equipment continuously miniaturise and provincial electricity, power consumption, small low dropout linear regulator (LDO) is becoming a switching power supply with linear regulator market mainstream. In order to achieve high performance and high speed, internal use of micro-computer or digital signal processor (DSP) technology has advanced by leaps and bounds every year in progress and development, at the same time, these micro-computers or digital signal processor essential power supply voltage is lower and lower. In addition, different manufacturing process corresponds to the voltage of the respective differences, and therefore requires a wide range of power supply voltage. To resolve this problem, the manufacturer started in the Middle voltage switching power supply setting, use LDO regulator with LSI power of new technologies. On the other hand, in the battery device also uses a large current LDO regulator in order to maximize the efficient use of battery voltage.

Use the DC/DC converter from obtaining high input power voltage 5V or so, and then use the linear regulator buck into 3.3 ~ 1.0V voltage, which is the usual power structure.

Such regulators are called subordinate linear regulators, in need of such a power structure to the device near a low input voltage supply more stable power supply. ROHM developed BD □ □ KA5 series product is suitable as a secondary linear regulators (Figure 1).

Secondary voltage regulator is seeking to further save space and more secure at the same time, constantly improve it in order to adapt to the DSP components such as narrow input voltage range and the high accuracy of must.

BD □ □ KA5 series 500mA current capacity while only, but the output phase compensation capacitor can support 1 μ F small ceramic capacitors, saves the space taken by regulators. At the same time, through the use of ROHM proprietary trimming techniques, the output voltage accuracy improves ± 1%. In addition, through the use of P-Channel MOS transistors as driven output transistors, even if you increase the load current to control circuit current and thermal design. Power supply input range is the most suitable 2.3V-5V 3.3V, 5V power supply input range. In addition, the output voltage specifications including 1.0V, 1.2V, 1.5V, 1.8V, 2.5V, 3.3V, adjustable input type and low voltage output, etc., products to meet different needs.

On the other hand, from battery direct gets output voltage standard fixed output and adjustable output remains essential, its peak output current of increasing every year.

ROHM's BA □ □ DD0 series is to have the current capability of LDO 2A (Figure 2). The series of achieving high output current of 2A, the output voltage accuracy improves ± 1%, and low-voltage 0.5V. Corresponding input voltage changes, avoiding the output voltage is lowered to low input voltage limit, ensures low voltage output started. In addition, the industry-standard pin configurations 78 series and ROHM previous 1A low saturation voltage regulator-compatible, easy replacement. Input voltage range (3 ~ 25V), output voltage range is from 1.5V, 1.8V, 2.5V, 3.0V, 3.3V, 5.0V, 9.0V, 12V to 16V.

Equipment in order to reduce power consumption without working part, in each region cut off the power of power management.

BD □ □ KA5 series and BA □ □ DD0 series of all models, all with under external logical interrupt all lines of shutdown switch function, the standby current consumption 0 μ A (typical), in favor of a low-power design.

These two series LDO regulator products have built-in protection circuits are as follows:

1. overcurrent protection circuit.

The use of automatic fall-protection circuit. If the overcurrent protection circuit starts to work, the output voltage drops, more focused output current, and hanging-type protection circuit can be compared, is short circuit, exception state chip heat consumption control in 1/3 ~ 1/5 (see Figure 3).

2. temperature protection circuit.

Temperature protection circuitry on the chip temperature exceeds Tj = 150 ° c automatically stops the output and to prevent overheating and damage caused by the chip, so as to achieve the purpose of the protection of the chip. If the chip temperature drop, you have to recover the hysteresis width output (Figure 4).

3. the overvoltage protection circuit.

Overvoltage protection circuit is built-in in BA □ □ DD0 series products, if the output appear above 25V, surge protection circuit starts to improve chip components pressure resistance, even if the input voltage exceeds the 50V, is also able to prevent chip damage (Figure 5).

4. high static pressure.

Output of electrostatic discharge pressure for human body model, you can achieve more than 6KV, in any environment with a high reliability.