Voltage controlled oscillators (VCOs) are critical and important component in the field of the communication network in electronics. Two traditionally used VCOs are complementary metal oxide semiconductor (CMOS) ring and inductor-capacitor (LC) tank based circuits, which are basic form of oscillators [
1,
2]. In the LC tank, oscillator on-chip combination of capacitors and inductors create large layout area [
3]. On other hand, CMOS ring inverter oscillators have provided advantage in controlling tuning range and no need for on-chip inductors [
4,
5]. Due to these reasons, CMOS ring oscillators provide flexibility for on-chip fabrication. CMOS based ring oscillator has become important building blocks in very large scale integration (VLSI) system with widely used in battery operated mobile devices and other communication and data processing systems with low power dissipation [
6]. A ring oscillator is combination of many delay stages with feedback element from output to input stage [
7]. In the electronic system, different types of ring VCO have been investigated using different types of delay cells like multiple feedback, dual delay paths and single ended delay cells [
7].There are some drawbacks of ring oscillators, like phase noise, power consumption and low oscillation frequency, which are important parameters in VCO [
8-
10]. Increasing the demand of portable devices including cellular phones, personal communication devices have aggressively improved attention for the low power consumption. Total power dissipation in VLSI circuits is combination of dynamic, static and leakage power. Dynamic power consumption due to switching of capacitance and static power is created by direct path between power supply (
Vdd) to ground (
Vss) [
6], minimum leakage power is also important in VLSI technology, it is known as off state power dissipation that arises from substrate injection and sub threshold currents, and the scaling of gate length further increases the leakage power. In the metal oxide semiconductor field effect transistors (MOSFETs) are controlling the bulk terminal of device, which offers enhanced performance parameter in term of power consumption [
11], to improve the standby leakage in CMOS circuits a reverse body biasing was normally used. In body biasing techniques, it makes utilization of body terminal as another control mechanism to dynamically tune the threshold voltage [
12]. Body bias technique defines the negative channel metal oxide semiconductor (NMOS) body bias, positive channel metal oxide semiconductor (PMOS) body bias, NMOS and PMOS joint body bias technique with ring oscillator. In NMOS and PMOS reverse body bias technique, all substrate terminals are connected to input supply, which reduce the leakage or wastage of power supply. In presented work, main objective is to reduce sub threshold leakage power consumption in VCO during off-to-on mode transition using reverse bias voltage. In Section 2, 45 nm low leakage ring VCO with three modified structures using reverse body biasing technique has been presented. The performance analysis and simulation results of VCO with reduction technique are presented in Section 3, comparison of presented technique and previous technique are shown in Section 4. Summary of the reported work is provided by Section 5.