Features
- Accepts input voltages above or below regulated output voltage
- Automatic bypass mode functionality
- Automatic and seamless transitions between buck and boost modes
- Input voltage range: 1.8V to 5.5V
- Selectable forced bypass power-saving mode
- Adaptive multilevel current limit scheme to optimize efficiency at low and high currents
- Output current: up to 800mA (VIN = 2.5V, VOUT = 3.3V)
- High efficiency: up to 98%
- 41μA quiescent current maximizes light-load efficiency
- Fully protected for over-temperature and undervoltage
- Small packages
- ISL9120 - 1.41mm x 1.41mm WLCSP
- ISL9120IR - 3mm x 3mm 12 Ld TQFN
Description
The ISL9120 and ISL9120IR are highly integrated buck-boost switching regulators that accept input voltages either above or below the regulated output voltage. The regulator automatically transitions between buck and boost modes without significant output disturbance. They also have automatic bypass functionality. When the input voltage is generally within 1% to 2% of the output voltage, there will be a direct bypass connection between the VIN and VOUT pins.
In addition to the automatic bypass functionality, the ISL9120 and ISL9120IR also have forced bypass functionality with the use of the BYP pin. The device is capable of delivering up to 800mA of output current (VIN = 2.5V, VOUT = 3.3V) and provides excellent efficiency due to its adaptive current limit Pulse Frequency Modulation (PFM) control architecture.
The ISL9120 and ISL9120IR are designed for stand-alone applications and support a 3.3V fixed output voltage or variable output voltages with an external resistor divider. The forced bypass power saving mode can be chosen if voltage regulation is not required. The device consumes less than 3.5µA of current over the operating temperature range in forced bypass mode.
The ISL9120 and ISL9120IR require only a single inductor and very few external components. Power supply solution size is minimized by the ISL9120 1.41mm x 1.41mm WLCSP package and the ISL9120IR 3mm x 3mm 12 Ld TQFN package.
Parameters
Attributes | Value |
---|---|
Topology [Rail 1] | Buck-Boost |
Outputs (#) | 1 |
Input Voltage (Min) [Rail 1] (V) | 1.8 |
Input Voltage (Max) [Rail 1] (V) | - |
Output Voltage (Min) [Rail 1] (V) | 1 |
Output Voltage (Max) [Rail 1] (V) | 5.2 |
Output Current (Max) [Rail 1] (A) | 0.8 |
IQ [Rail 1] (µA) | 41 |
Control Type | Hysteretic Mode |
POR | Yes |
SYNCH Capability | No |
Peak Efficiency (%) | 98 |
Qualification Level | Standard |
Application Block Diagrams
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Bluetooth Wireless Headphones with Extended Battery Life
Wireless headphones with extended battery life, advanced security, and compact design.
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Health Monitor Band
A wearable health band that reads the user's heart rate and respiration using a piezoelectric sensor.
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Wearable Smart Ring for Health and Connectivity
Smart rings combine health tracking with NFC charging and payments plus Bluetooth LE for efficient performance.
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Solar-Powered Location Tracker
The solar-powered location tracker offers modular design, versatile connectivity, and PV energy harvesting.
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PC Water Cooling System with Wireless Control
Advanced PC water cooler with wireless control, efficient heat dissipation, and flexible configurations.
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Automated Meter Reader (AMR) Retrofit Module
AMR retrofit module offers cost-efficient metrology, flexible MCU design, and extended battery life.
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Additional Applications
- Smartphones and tablets
- Portable consumer and wearable devices
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Sample Code
Simulation Models
The ISL9120 offers designers the flexibility to cover a variety of design needs by operating from a Vin of 1.8V to 5.5V and an adjustable output voltage from 1V to 5.2V. Its adaptive PFM operation with forced bypass mode and 2A switches support both low load and high load currents with high efficiency, ensuring longer battery life and less heat buildup. The regulator also delivers 800mA current with 2.5V input and 3.3V output.
Transcript
Hi, my name is Gaurav Mital. I'm an applications engineer for the Intersil's mobile power product line. Today I'm gonna be talking about a new power product solution which is going to be a good fit for wearables and mobile systems.
Wearables are becoming very popular and system designers are being constantly challenged to create solutions which are smaller, more efficient and cost effective, and Intersil is committed to be a leader in providing solutions for these products.
A typical power solution for a wearable device uses three DC/DC regulators and three to five LDOs depending on the number of applications. As you can see, Intersil's existing power solutions caters to all blocks but we identified a couple of opportunities where using a buck-boost can be more efficient.
How does the buck-boost add value to the system? A lithium-ion battery voltage varies from 4.2V down to 2.7V. For a system which requires 3.3V, a buck-boost regulator helps in utilizing broader range of the battery.
Also, multiple applications in the mobile are powered by the LDOs like the Wi-Fi and the LCD module which gives buck-boost an edge as it provides better efficiency in these conditions.
When the VBAT is near 3.3V, a burst current can cause local node voltage to droop to 2.7V which may shut down the application and this can also be avoided by using a buck-boost regulator.
I'm excited to share that Intersil has developed a new compact, highly efficient, low powered buck-boost regulator ideal for wearable and hand-held applications, the ISL9120.
The ISL9120 operates from 1.8V to 5.5V. The output voltage is adjustable from 1V to 5.2V which provides flexibility to cover a variety of design needs. The adaptive PFM operation helps in getting excellent efficiency and low output ripple. This part is capable of delivering 800mA current with 2.5V in and 3.3V out. It is offered in a 1.4mm x 1.4mm chip scale package.
The ISL9120 offers excellent efficiency for both low load and high load conditions. The adaptive PFM operation helps in attaining up to 98% efficiency at higher loads and more than 86% at lower load conditions. This ensures less power drain and less heat build up which extends the battery life and saves board space by eliminating the need for external heat sinks.
During a systems stay alive condition where regulation is not a must, the power can be put in force bypass mode in which the power consumption reduces to ultra-low quiescent current of less than 0.5μA. As the part is only 1.4mm x 1.4mm, the overall solution size is very small. This helps in getting a very competitive price solution.
The 98% efficiency, low power consumption and ultra-small PCB footprint, the ISL9120 simplifies design and extends battery life. The wide input and output voltage range provides flexibility to cover a variety of design needs.
To order samples, eval boards or download a datasheet, please visit the ISL9120 product page. Thank you for watching.
Intersil talks about how a buck-boost regulator adds value in a mobile/wearable device and introduces the ISL9120 buck-boost switching regulator which is highly compact, with excellent efficiency. We will look at some of its key features, and point out some ideal applications for this part in the wearables and mobile space.
Transcript
ISL9120 Buck-Boost Switching Regulator
Handheld Power Products
Welcome to the ISL9120 buck-boost switching regulator product overview. Today, we will be talking about how a buck-boost regulator adds value in a mobile/wearable device and introduce Intersil’s ISL9120 buck-boost switching regulator which is highly compact, with excellent efficiency. We will look at some of its key features, and point out some ideal applications for this part in the wearables and mobile space.
Why a Buck-Boost Is Needed In a Mobile Device?
How does a buck-boost add value in a mobile system? An Li-ion battery ranges from 4.2V to 2.7V and in a system to be powered by 3.3V, the buck-boost helps in utilizing a broader range of the battery. Multiple blocks in a mobile system are powered by an LDO such as Wi-Fi, Bluetooth, SD card, and LCD module. A buck-boost helps in optimizing the efficiency in these application as a pre-regulator and provides better system efficiency. When the battery voltage is close to 3.3V, a burst current can cause a local node voltage to droop to 2.7V, which is below the regulation point and hence can cause the application to shut down. This can be avoided by using a buck-boost as a pre-regulator.
Prevent Brownout
As discussed in the previous slide, when multiple applications are being used together, there can be narrow pulse high current as high as 4A. As an Li-ion battery inherently has ~100 to 200mΩ ESR, the voltage drop across it can cause the local node voltage to droop below 2.85V and will cause the EMMC to shut off. This behavior is highly undesirable. If we use a buck-boost with VOUT of 2.9V to power the LDO, the buck-boost will block this perturbation without affecting the input to the LDO, hence avoiding the brownout issue.
Compact High Efficiency Buck-Boost with Bypass
The ISL9120 is a highly efficient and compact buck-boost regulator. ISL9120 operates from 1.8V to 5.5V. The output voltage is adjustable from 1V to 5.2V which provides flexibility to cover a variety of design needs. The adaptive PFM operation helps in getting excellent efficiency and low output ripple. This part is capable of delivering 800mA current with 2.5V in and 3.3V out. The ISL9120 is offered in a 1.4mm x 1.4mm WLCSP package. During system stay alive conditions when regulation is not a must, the part can be put in forced bypass mode, in which the power consumption reduces to ultra-low quiescent current of <0.5μA.
Fixed vs. Adaptive Current Limit Schemes
The adaptive PFM current limit scheme helps in reducing both VOUT ripple and increasing the efficiency as compared to the fixed current scheme. As the RMS current in the inductor is lower for a low load condition, it helps lower the conduction losses.
To optimize efficiency across the output current range, the ISL9120 implements a multi-level current limit scheme with 32 levels between 350mA and 2A. The transition from one level to the other is determined by the number of pulses in a PFM burst (pulse count). The lower peak current also helps in attaining smaller VOUT ripple.
At a given peak current limit level, the pulse count increases as the output current increases. When the pulse count reaches the upper threshold at the existing current limit, the current limit will switch to the next higher level. Similarly, if the pulse count reaches the lower threshold at the existing current limit, the device will switch to the next lower level of peak current limit. If the pulse count reaches the upper threshold at the highest current limit, the current limit will not rise any further.
ISL9120 Efficiency Plot
The ISL9120 offers excellent efficiency for both low load and high load conditions. The adaptive PFM operation helps in attaining up to 98% efficiency at higher load and >86% at lower load conditions. This ensures less power drain and less heat buildup which extends the battery life and saves board space by eliminating the need for external heat sinks.
Applications
The ISL9120 with its excellent efficiency and compact size is highly suitable for wearables/mobile and IoT devices. Applications like the heart rate sensor and the display in wearables require 3.3V to 3.6V input and a buck-boost is a good fit for it. Smartphones and tablets have the Wi-Fi module and LCD module which have similar VIN requirements, making the ISL9120 favorable for these applications.
Summary
With high efficiency, low power consumption and an ultra-small PCB footprint, the ISL9120’s adaptive PFM current limit architecture helps to extend battery life and simplify design. The wide input and output voltage ranges provide flexibility to cover a variety of design needs.
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Blog Post
Oct 12, 2020
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